Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our consolidated financial statements and related notes and other financial information included elsewhere in this Annual Report on Form 10-K. For discussion and analysis related to our financial condition and results of operations comparing the year ended December 31, 2023 ("2023") to the year ended December 31, 2022, refer to Part II, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations in our Annual Report on Form 10-K for 2023, which was filed with the Securities and Exchange Commission on February 27, 2024. This discussion and analysis contain forward-looking statements based upon our current beliefs, plans and expectations that involve risks, uncertainties and assumptions, such as statements regarding our plans, objectives, expectations, intentions and beliefs. Our actual results and the timing of events could differ materially from those anticipated in these forward-looking statements as a result of various factors, including those set forth under the section titled “Risk Factors” and elsewhere in this Annual Report on Form 10-K. You should carefully read the “Risk Factors” section of this Annual Report on Form 10-K to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements. Please also see the section titled “Special Note Regarding Forward-Looking Statements.”

Overview

We are a clinical-stage vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases. We are re-engineering the way highly complex vaccines are made through the XpressCFTM cell-free protein synthesis platform. Unlike conventional cell-based approaches, our system for producing difficult-to-make proteins and antigens is intended to develop and deliver high-fidelity vaccines with enhanced immunological benefits that are beyond the capabilities of conventional approaches.

Our pipeline includes:

•PCV candidates that we believe are among the broadest-spectrum PCV candidates currently in development, targeting the approximately $8 billion global pneumococcal vaccine market. Pneumococcal disease ("PD") is an infection caused by Streptococcus pneumoniae bacteria. It can result in invasive pneumococcal disease (“IPD”), including meningitis and bacteremia, and non-invasive PD, including pneumonia, otitis media and sinusitis. Our broad-spectrum, carrier-sparing PCV candidates, VAX-31, VAX-24 and VAX-XL, are designed to improve upon standard-of-care PCVs for both adults and children by covering the serotypes that are responsible for increasing portions of IPD in circulation and are associated with high case-fatality rates, antibiotic resistance and meningitis, while maintaining coverage of previously circulating strains that are currently contained through continued vaccination.

◦PCV Franchise Adult Indication:

▪VAX-31 is a 31-valent, broad-spectrum, carrier-sparing investigational PCV being developed for the prevention of IPD and pneumonia. VAX-31 is the broadest-spectrum PCV in the clinic, and has the potential to provide protection against both currently circulating and historically prevalent serotypes. VAX-31 was designed to increase coverage, in a single vaccine, to approximately 95% of IPD and approximately 88% of pneumococcal pneumonia circulating in adults in the United States aged 50 and older, with the potential to provide an incremental 14-34% of coverage for IPD and an incremental 19-31% of coverage for pneumococcal pneumonia over current standard-of-care adult PCVs.

•In September 2024, we announced positive topline results from a Phase 1/2 study of VAX-31 in adults. The VAX-31 Phase 1/2 clinical study was a randomized, observer-blind, active-controlled, dose-finding clinical study designed to evaluate the safety, tolerability and immunogenicity of a single injection of VAX-31 at three dose levels (Low, Middle and High) and compared to Prevnar 20® ("PCV20") in 1,015 healthy adults aged 50 and older. In the Low, Middle and High Doses, all serotypes were dosed at 1.1mcg, 2.2mcg and 3.3mcg, respectively, except serotypes 1, 5 and 22F, which were dosed at 1.65mcg, 3.3mcg, and 4.4mcg, respectively. The Phase 1 portion of the study included 64 healthy adults 50 to 64 years of age and the Phase 2 portion included 951 healthy adults 50 years of age and older. The immunogenicity objectives of the study included an assessment of the induction of antibody responses at Month 1, based on opsonophagocytic activity (“OPA”) and immunoglobulin G ("IgG"), at each of the

100

Table of Contents

three VAX-31 doses and compared to PCV20 for the 20 serotypes in common, as well as for the additional 11 serotypes contained in VAX-31, but not in PCV20.

In the Phase 1/2 study, VAX-31 was observed to be well tolerated and demonstrated a safety profile at all doses studied through the full six-month evaluation period similar to PCV20. VAX-31 showed robust OPA immune responses for all 31 serotypes at all doses studied. At the Middle and High Doses, VAX-31 met or exceeded the regulatory immunogenicity criteria for all 31 serotypes and, at the Low Dose, for 29 of 31 serotypes. At the VAX-31 High Dose, average OPA immune responses were greater for 18 of 20 serotypes compared to PCV20 (geometric mean ratio (“GMR”) greater than 1.0), with seven of these serotypes achieving statistically higher immune responses compared to PCV20. At the Middle Dose, 13 of 20 serotypes had a GMR greater than 1.0 and five serotypes achieved statistically higher immune responses compared to PCV20. At the Low Dose, 18 of 20 serotypes met the OPA response non-inferiority criteria, 8 of 20 serotypes had a GMR greater than 1.0 and three serotypes achieved statistically higher immune responses. For all 11 incremental serotypes unique to VAX-31, and not in PCV20, all three doses met the superiority criteria.

Based on these positive results, we selected the High Dose of VAX-31 to advance to an adult Phase 3 program.

•In November 2024, we announced that the FDA granted breakthrough therapy designation ("BTD") for VAX-31 for the prevention of IPD in adults and, in August 2025, we announced that the FDA expanded the BTD for VAX-31 to include the prevention of pneumonia caused by Streptococcus pneumoniae.

•In December 2025, following an FDA End-of-Phase 2 meeting, we announced that the first participants were dosed in a Phase 3 pivotal, non-inferiority trial evaluating VAX-31 for the prevention of IPD and pneumonia in adults compared to standard-of-care PCVs ("OPUS-1"). We expect to announce topline safety, tolerability and immunogenicity data from this study in the fourth quarter of 2026.

•In January 2026, we announced the initiation of an additional Phase 3 trial evaluating VAX-31 when administered concomitantly with a licensed, high-dose seasonal influenza vaccine in pneumococcal-naïve adults aged 50 years and older (“OPUS-2”). In February 2026, we announced the initiation of a separate Phase 3 study evaluating VAX-31 in adults previously vaccinated with a lower-valency pneumococcal vaccine (“OPUS-3”). We expect to report safety, tolerability and immunogenicity data from the OPUS-2 and OPUS-3 studies in the first half of 2027. We are also planning for a manufacturing consistency study (e.g., a lot-to-lot study).

◦PCV Franchise Pediatric Indication:

▪VAX-31 is a 31-valent, broad-spectrum, carrier-sparing investigational PCV also being developed for the prevention of IPD in children. VAX-31 is the broadest-spectrum PCV in the clinic designed to cover approximately 92% of IPD in U.S. children under five years of age and approximately 96% of otitis media due to Streptococcus pneumoniae in U.S. children five years of age or under.

▪In December 2024, we announced that the first participants were dosed in the first stage of a Phase 2, randomized, dose-finding study of VAX-31 in infants. Stage 1 of the study evaluated the safety and tolerability of VAX-31 at three dose levels (Low, Middle and High) and compared to PCV20 in 48 infants in a dose-escalation approach. In the Low, Middle and High Doses, all serotypes were dosed at 1.1mcg, 2.2mcg and 3.3mcg, respectively, except serotypes 1, 5 and 22F, which were dosed at 1.65mcg, 3.3mcg, and 4.4mcg, respectively. Participants who received VAX-31 in Stage 1 continued the standard dosing regimen as part of Stage 2.

▪In February 2025, we announced that the Phase 2, randomized, dose-finding study of VAX-31 in healthy infants had advanced to the second stage of the study. Stage 2 of the study is evaluating the safety, tolerability and immunogenicity of VAX-31 at the same three dose levels evaluated in Stage 1 and compared to PCV20. In line with

101

Table of Contents

recommendations from the ACIP, the study design includes a primary immunization series consisting of three doses given at two months, four months and six months of age, followed by a subsequent booster dose at 12-15 months of age.

▪In September 2025, we announced advancement of the VAX-31 infant Phase 2 randomized, dose-finding study to the third and final stage following modifications to the protocol to add a new dose arm to evaluate a VAX-31 Optimized Dose (majority of serotypes dosed at 4.4mcg and the balance dosed at 3.3mcg) and discontinue enrollment in the Low Dose arm. The Middle and High Dose arms continued as planned.

▪The modified study is evaluating the safety, tolerability and immunogenicity of VAX-31 and compared to PCV20 in 900 participants, including the 100 participants previously enrolled in the Low Dose arm.

▪In January 2026, we announced that we completed enrollment of this study. We expect to announce topline safety, tolerability and immunogenicity data from the primary three-dose immunization series and booster dose either sequentially or together by the end of the first half of 2027.

▪Pending the VAX-31 Phase 2 infant study readout, we plan to initiate a Phase 3 program in infants with an Optimized Dose formulation of VAX-24 or VAX-31.

▪VAX-24 is a 24-valent, broad-spectrum, carrier-sparing investigational PCV being developed for the prevention of IPD in infants, and it covers more serotypes than any pneumococcal infant vaccine on the market today.

•In March 2025, we announced positive topline, interim data from the VAX-24 infant Phase 2 study, a randomized, observer-blind, dose-finding two-stage clinical study evaluating the safety, tolerability and immunogenicity of VAX-24 in healthy infants that enrolled 803 participants.

•In November 2025, we announced final safety, tolerability, and immunogenicity results from the VAX-24 infant Phase 2 study that were consistent with the positive interim data reported in March 2025 and showed that VAX-24 elicited robust, dose-dependent immune responses, with little to no evidence of carrier suppression observed. The final data analysis included full 6-month safety results and complete post-dose 3 (primary immunization series) and post-dose 4 (booster dose) IgG and OPA results. The key immunogenicity endpoints included an assessment of immune responses for each of the VAX-24 dose levels (Low, Mid, Mixed) in comparison with PCV20 for the 20 common and 4 unique serotypes in VAX-24. At 1-month post-dose 3 and post-dose 4, immune responses were assessed based on serotype-specific IgG seroconversion rates (IgG threshold value of ≥0.35mcg/mL). IgG GMRs were also assessed at 1-month post-dose 3 and post-dose 4, along with other key immunogenicity endpoints, including OPA.

In this study, VAX-24 was well-tolerated and demonstrated a safety profile similar to PCV20 across all doses studied. Post-dose 3 and post-dose 4, all VAX-24 doses evaluated demonstrated robust IgG and OPA immunogenicity responses.

•Post-dose 3, all VAX-24 doses met target precedent Phase 2 non-inferiority criteria on relative seroconversion rates (lower limit of the 95% confidence interval for the difference between the proportion of participants achieving the pre-defined seroconversion rate (IgG concentration ≥0.35 mcg/mL) is > -15% for each serotype) for the highest circulating serotypes, as defined by the percentage of IPD caused in individuals <5 yrs of age in the U.S. in 2023 based on the U.S. Center for Disease Control ("CDC") active bacterial core ("ABC") surveillance data, contained in VAX-24. The Low and Mid doses met the seroconversion rate criteria for 20 of 24 serotypes overall and the Mixed Dose met such criteria for 19 of 24 serotypes. The Mid and Mixed Doses met the target Phase 2 IgG GMR point estimate of >0.6 for 21 of 24 serotypes.

102

Table of Contents

•Post-dose 4, all VAX-24 doses met our target Phase 2 IgG GMR point estimate of >0.6 for the three highest circulating serotypes contained in VAX-24. The Mixed Dose met this target for 19 of 24 serotypes overall and the Mid dose met this target for 18 of 24 serotypes. Post-dose 4, VAX-24 elicited robust memory responses across all doses for all serotypes.

•Additionally, the four incremental serotypes unique to VAX-24 that provide expanded serotype coverage relative to PCV20 elicited robust immune responses and met all target criteria across all endpoints at all doses evaluated.

•The final positive data from the VAX-24 infant Phase 2 dose-finding study further validated our rationale for exploring higher doses in the ongoing VAX-31 infant Phase 2 study.

◦VAX-XL is a third-generation PCV candidate designed to provide the broadest coverage of any PCV currently in development.

•VAX-A1, a novel conjugate vaccine candidate designed to prevent disease caused by Group A Streptococcus (“Group A Strep”). Group A Strep is pervasive globally and causes an estimated 800 million cases of illness annually, including pharyngitis, or strep throat, and certain severe invasive infections and sequelae. There is currently no vaccine against Group A Strep, which is one of the leading infectious disease-related causes of death and disability worldwide and a significant contributor to the prescription of antibiotics in children. We believe we have demonstrated preclinical proof of concept for VAX-A1, the data for which were published in December 2020. We plan to initiate a Phase 1 adult study for VAX-A1 in 2026, with the primary objective of assessing safety and tolerability.

•VAX-GI, a novel preclinical vaccine candidate being developed as a preventative treatment for dysentery and shigellosis, which is caused by Shigella bacteria. Shigella is a bacterial illness estimated to cause 80 million to 165 million cases of disease and 600,000 deaths annually, mostly among children. The central antigen in VAX-GI is IpaB, a well-appreciated antigen that other developers have been unable to produce in an amount sufficient to enable a commercial product. With our cell-free technology, we believe we can produce this antigen at substantially improved yields, allowing for commercial-scale production. VAX-GI is being developed in collaboration with the University of Maryland, Baltimore as well as with partial funding from two research grants awarded by the National Institutes of Health (“NIH”). As part of our continued focus on strategic capital deployment and in order to prioritize our resources towards our PCV franchise, we announced in August 2025 that we had paused the advancement, beyond preclinical development, of VAX-GI while remaining confident in its potential and preserving the option to advance the program in the future.

•Other discovery-stage programs that leverage our cell-free protein synthesis platform, which, if proven successful in preclinical studies, could also be advanced into IND-enabling activities and clinical studies.

Since January 1, 2025, key developments affecting our business include the following:

PCV Franchise Adult Indication:

•FDA Expanded VAX-31 Adult BTD to Include Prevention of Pneumonia Caused by Streptococcus Pneumoniae in Addition to IPD: In May 2025, the FDA expanded the adult BTD for VAX-31 to include the prevention of pneumonia caused by Streptococcus pneumoniae in addition to the prevention of IPD based on the positive topline results from the VAX-31 adult Phase 1/2 study, indicating that VAX-31 may demonstrate substantial improvement over existing therapies.

•Advanced Comprehensive Phase 3 Clinical Program to Support Planned BLA Submission and Validate VAX-31 as Potential New Standard-of-Care Adult PCV to Prevent IPD and Pneumonia: In August 2025, we announced that through a series of interactions with the FDA, including an End-of-Phase 2 meeting, regarding the VAX-31 adult Phase 3 clinical program, the FDA provided input on the adult commercial licensure requirements, including the approximate number of study participants in the Phase 3 program; key immunogenicity and safety endpoints for the pivotal, non-inferiority study; and a continued indication that the scale of the planned immunogenicity and safety assessments are in line with precedent requirements and will be sufficient to support potential licensure. Additionally, as part of ongoing discussions granted under the VAX-31 adult BTD, the FDA provided input on the chemistry, manufacturing and controls (“CMC”) licensure requirements in support of our

103

Table of Contents

path to delivering a BLA submission. The VAX-31 High Dose (all serotypes dosed at 3.3mcg or 4.4mcg) has been selected to advance into Phase 3.

•Initiated Phase 3 OPUS-1 Trial: In December 2025 we announced we dosed the first participants in the OPUS-1 trial, with topline data expected in the fourth quarter of 2026. This trial is evaluating the safety, tolerability and immune responses of VAX-31 in approximately 3,560 adults aged 50 and older through direct, head-to-head comparisons with both Capvaxive® ("PCV21") and PCV20, the current standard-of-care PCVs, with the objective of establishing a best-in-class profile for VAX-31. The trial is also evaluating the safety, tolerability and immune responses of VAX-31 in approximately 440 adults aged 18-49. OPUS-1 is being conducted at approximately 50 sites in the United States.

•Initiated Phase 3 OPUS-2 and OPUS-3 Trials: In January 2026, we dosed the first participants in OPUS-2, a Phase 3 descriptive study designed to evaluate the safety, tolerability and immunogenicity of VAX-31 when administered concomitantly with, or one month following, a licensed, high-dose seasonal influenza vaccine in approximately 1,300 pneumococcal-naïve adults aged 50 years and older (defined as having no known prior history of IPD, pneumococcal pneumonia, or receipt of any licensed or investigational pneumococcal vaccine). OPUS-2 is being conducted at approximately 25 sites in the United States. In February 2026, we dosed the first participants in OPUS-3, a Phase 3 descriptive study evaluating the safety, tolerability and immunogenicity of a single dose of VAX-31 in approximately 720 adults aged 50 years and older who have previously received lower-valency pneumococcal vaccines. OPUS-3 is being conducted at approximately 30 sites in the United States. We expect to report safety, tolerability and immunogenicity data from the OPUS-2 and OPUS-3 studies in the first half of 2027. We are also planning for a manufacturing consistency study (e.g. a lot-to-lot study).

•Advancing Toward BLA Submission: Subject to the results of the Phase 3 studies, which are expected to read out in 2026 and 2027, we plan to submit a BLA shortly following the completion of the last Phase 3 study.

PCV Franchise Infant Indication:

•Completed Enrollment of Ongoing VAX-31 Infant Phase 2 Dose-Finding Study: In August 2025, we announced that we had modified the ongoing VAX-31 infant Phase 2 randomized, dose-finding study to add a new dose arm to evaluate a VAX-31 Optimized Dose with the majority of serotypes dosed at 4.4mcg and the balance dosed at 3.3mcg. Both the Middle Dose and High Dose VAX-31 arms in the study are proceeding as planned while we elected to discontinue enrollment in the Low Dose arm. In September 2025, we announced that the first participants had received the Optimized Dose and subsequently announced in January 2026 that we had completed enrollment of the study. The modified study will evaluate VAX-31 in 900 dosed participants, including the 100 participants previously enrolled in the Low Dose arm. We expect to announce topline safety, tolerability and immunogenicity data from the primary three-dose immunization series and booster dose either sequentially or together by the end of the first half of 2027.

•Reported Positive Interim and Final VAX-24 Infant Phase 2 Dose-Finding Study Data: In March 2025, we announced positive topline, interim data from the VAX-24 infant Phase 2 study that enrolled 803 participants. In November 2025, we announced the final safety, tolerability, and immunogenicity results from the study, which were consistent with the positive interim data reported in March 2025 and showed that VAX-24 elicited robust, dose-dependent immune responses, with little to no evidence of carrier suppression observed. The final data analysis included full 6-month safety results and complete post-dose 3 (primary immunization series) and post-dose 4 (booster dose) IgG and OPA results. The totality of data from this study affirms the Company’s strategy to include the higher doses that are being evaluated in the ongoing VAX-31 infant Phase 2 dose-finding study.

Other Pipeline Programs:

•Advancing VAX-A1, a Vaccine Candidate Designed to Prevent Disease Caused by Group A Strep, Into the Clinic: In February 2026, we announced we are planning to initiate a Phase 1 adult study for VAX-A1, a prophylactic vaccine candidate designed to prevent disease caused by Group A Strep, in 2026 with the primary objective of assessing safety and tolerability. Group A Strep remains a major global cause of morbidity and mortality in adults and children and is a leading driver of antibiotic use, underscoring the significant public health burden.

•Introduced Development of VAX-XL, Third-Generation PCV Candidate Designed to Further Expand Disease and Serotype Coverage: In March 2025, we announced VAX-XL, our third-generation PCV candidate designed to provide the broadest coverage of any PCV currently in development for infants or adults.

104

Table of Contents

Equity Financing:

•Completed Public Offering Generating Gross Proceeds of $632.5 million: In February 2026, we completed an underwritten public offering of 12,650,000 shares of common stock, which included the full exercise of the underwriters' option to purchase an additional 1,650,000 shares, at a public offering price of $50.00 per share. The aggregate gross proceeds to us from this offering were $632.5 million, before deducting underwriting discounts and commissions and other offering expenses payable by us.

Other Business:

•Appointed Dr. Olivier Brandicourt to our Board of Directors: In May 2025, we appointed Dr. Olivier Brandicourt to our Board of Directors. Dr. Brandicourt is a veteran biopharmaceutical industry executive and the former Chief Executive Officer of Sanofi S.A. and Bayer HealthCare AG. He brings a wealth of expertise, with significant experience in commercial strategy and execution within the global vaccine market. Dr. Brandicourt is currently a Senior Advisor at Blackstone Life Sciences and serves on the boards of Alnylam Pharmaceuticals, Inc., AvenCell Therapeutics, Inc., BeOne Medicines Ltd. and Dewpoint Therapeutics, Inc.

•Appointed Chris Griffith as Chief Business and Strategy Officer: In July 2025, Chris Griffith joined Vaxcyte as Chief Business and Strategy Officer. With more than 20 years of experience spanning corporate and business development, portfolio strategy and business operations, Mr. Griffith brings deep expertise to this newly expanded role. His leadership will help ensure strong cross-functional alignment and execution as we advance our late-stage programs and prepare for the next phase of growth.

•Announced Plan to Establish Fill-Finish Manufacturing in North Carolina as Key Element of Long-Term U.S. Commercial Supply Strategy Representing Up to $1 Billion in Manufacturing and Services: In September 2025, we announced a new agreement with Patheon Manufacturing Services, LLC, part of Thermo Fisher Scientific (collectively, "Thermo Fisher") to provide custom commercial fill-finish capacity for our broad-spectrum PCVs at Thermo Fisher's Greenville, North Carolina facility. The initiative, which includes both manufacturing and related services, represents a long-term U.S. commercial manufacturing commitment of up to $1 billion.

•Appointed Mike Mullette as Chief Commercial Officer to Lead Commercialization Strategy and Execution: In October 2025, Michael Mullette joined Vaxcyte as Chief Commercial Officer, bringing more than 20 years of global experience in vaccines and biopharmaceuticals, including senior leadership roles at Moderna, Sanofi Pasteur and Lykos Therapeutics. As part of our strategy to prepare for future commercialization of our PCV programs, Mr. Mullette will lead the continued development and execution of global commercialization, including pre-launch planning and cross-functional readiness. He brings extensive launch leadership, having led Moderna’s first ever commercial organization in North America during the COVID-19 pandemic and launched multiple vaccines at Sanofi Pasteur across the U.S., France, Japan, Australia and Canada.

Since our inception in November 2013, we have devoted substantially all of our resources to performing research and development, undertaking preclinical studies, advancing our vaccine candidates through clinical trials, enabling manufacturing activities in support of our product development efforts, acquiring and developing our technology and vaccine candidates, organizing and staffing our company, performing business planning, establishing our intellectual property portfolio and raising capital to support and expand such activities. We do not have any products approved for sale and have not generated any revenue from product sales. To date, we have financed our operations primarily with proceeds from the sales of our common stock, pre-funded warrants to purchase our common stock and, prior to our initial public offering (“IPO”) in June 2020, redeemable convertible preferred stock. We will continue to require additional capital to develop and commercialize our vaccine candidates and fund operations for the foreseeable future. Accordingly, until such time as we can generate significant revenue from sales of our vaccine candidates, if ever, we expect to finance our cash needs through public or private equity or debt financings, third-party (including government) funding and marketing and distribution arrangements, as well as other collaborations, strategic alliances and licensing arrangements, or any combination of these approaches.

We have incurred net losses in each year since inception and expect to continue to incur net losses in the foreseeable future. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending in large part on the timing of our clinical trials and manufacturing activities, and our expenditures on other research and development activities. Our net losses were $766.6 million, $463.9 million, and $402.3 million for the years ended December 31, 2025, 2024 and 2023, respectively. As of December 31, 2025, we had an accumulated deficit of $2,154.9 million and cash, cash equivalents and investments of $2,442.6 million. We believe our cash, cash equivalents and investments will be sufficient to fund our

105

Table of Contents

operating expenses and capital expenditure requirements through at least 12 months from the filing date of this Annual Report on Form 10-K.

We do not expect to generate any revenue from commercial product sales unless and until we successfully complete development and obtain regulatory approval for one or more of our vaccine candidates, which we expect will take a number of years. We expect our expenses will increase substantially in connection with our ongoing activities, as we:

•advance our vaccine candidates through preclinical studies and clinical trials;

•progress in the scale-up of our manufacturing capabilities, in particular to prepare for the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population;

•incur additional costs that may be required for secondary supply sources;

•require the manufacture of supplies for our clinical trials;

•conduct clinical trials, in particular VAX-31 and VAX-24;

•pursue regulatory approval of our vaccine candidates;

•establish additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population;

•hire additional personnel;

•scale medical affairs and commercial infrastructure to support anticipated product launches;

•expand our facilities to support our growing workforce and lab activities;

•acquire, discover, validate and develop additional vaccine candidates; and

•obtain, maintain, expand and protect our intellectual property portfolio.

We rely and will continue to rely on third parties to conduct our preclinical studies and clinical trials and for manufacturing and supply of our vaccine candidates. We have no internal manufacturing capabilities, and we will continue to rely on third parties, of which the main suppliers are single-source suppliers, for our preclinical and clinical trial materials. Given our stage of development, we do not yet have a marketing or sales organization and have a limited commercial infrastructure. Accordingly, if we obtain regulatory approval for any of our vaccine candidates, we also would expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution.

Because of the numerous risks and uncertainties associated with vaccine development, we are unable to predict the timing or amount of increased expenses or when or if we will be able to achieve or maintain profitability. Even if we are able to generate revenue from the sale of our vaccines, we may not become profitable. If we fail to become profitable or are unable to sustain profitability on a continuing basis, then we may be unable to continue our operations at planned levels and may be forced to reduce our operations.

Certain Significant Relationships

Lonza Ltd. (“Lonza”)

Development and Manufacturing Services Agreements

In April 2022, we entered into a non-exclusive development and manufacturing services agreement with Lonza effective as of March 22, 2022, which was subsequently amended on May 12, 2022, November 21, 2022 and October 31, 2023 (as amended, the “2022 Lonza DMSA”). Pursuant to the 2022 Lonza DMSA, Lonza is obligated to perform services, including manufacturing process development and clinical manufacture and supply of our proprietary PCV candidates. Subject to the terms and conditions set forth in the 2022 Lonza DMSA, Lonza has granted to us a non-exclusive, worldwide, fully paid-up, irrevocable, transferable license, including the right to grant sublicenses, under the New General Application Intellectual Property, to research, develop, make, have made, use, sell and import the Product. Unless earlier terminated, the 2022 Lonza DMSA shall remain in place for a period of five years. Either party may terminate the 2022 Lonza DMSA for any reason on prior written notice to the other party, provided that Lonza may not exercise such right until a specified future date. In addition, either party may terminate the 2022 Lonza DMSA (i) within a given time period upon any material breach that is left uncured by the other party, or (ii) immediately if the other party becomes insolvent. We may also terminate the 2022 Lonza DMSA upon an extended force majeure event. Upon expiration and/or termination of the 2022

106

Table of Contents

Lonza DMSA and/or any purchase order, we will pay Lonza for all service rendered, all costs incurred, all unreimbursed capital equipment and any cancellation fees (each term as defined in the 2022 Lonza DMSA).

In February 2023, we entered into another non-exclusive development and manufacturing services agreement with Lonza effective as of March 1, 2023 (the “2023 Lonza DMSA”). Pursuant to the 2023 Lonza DMSA, Lonza will perform manufacturing process development and the manufacture of components for our PCV candidates, including the polysaccharide antigens, our proprietary eCRM protein carrier and conjugated drug substances. Subject to the terms and conditions set forth in the 2023 Lonza DMSA, Lonza has granted to us a non-exclusive, worldwide, fully paid-up, transferable license, including the right to grant sublicenses (subject to the prior written consent of Lonza), under the New General Application Intellectual Property, to use, sell and import the Product manufactured under the 2023 Lonza DMSA (but no other products). Unless earlier terminated, the 2023 Lonza DMSA shall remain in place for a period of five years and shall automatically renew for one additional two-year period unless either party provides written notice of non-renewal at least two years prior to the fifth anniversary of the effective date. We may terminate the 2023 Lonza DMSA for any reason on prior written notice to the other party on a Project Plan-by-Project Plan basis. Either party may terminate the 2023 Lonza DMSA (i) within a given time period upon any material breach that is left uncured by the other party, (ii) immediately if the other party becomes insolvent, is dissolved or liquidated, makes a general assignment for the benefit of its creditors, or files or has filed against it, a petition in bankruptcy or has a receiver appointed for a substantial part of its assets, (iii) upon an extended force majeure event, or (iv) if it becomes apparent to either party at any stage in the provision of the Services that it will be impossible to complete the Services for scientific or technical reasons despite exercise of best commercial efforts by both parties. Pursuant to the reason for termination and the party initiating the termination, we will pay Lonza for some combination of services rendered, costs incurred, unreimbursed capital equipment and/or any cancellation fees. Upon an extended force majeure event, neither party shall have any further liability to the other party (each term as defined in the 2023 Lonza DMSA).

Under each of the 2022 Lonza DMSA and 2023 Lonza DMSA (collectively, the “Lonza Agreements”), we pay Lonza agreed-upon fees for their performance of development and manufacturing services and pass-through expenses incurred by Lonza for raw materials, as well as customary procurement and handling fees. Under each Lonza Agreement, we own all rights, title and interest in and to any and all New Customer Intellectual Property (as defined in each Lonza Agreement), and Lonza owns all rights, title and interest in New General Application Intellectual Property (as defined in each Lonza Agreement).

Commercial Manufacturing and Supply Agreement

On October 13, 2023, we entered into a pre-commercial services and commercial manufacturing supply agreement with Lonza (the “Lonza Commercial Manufacturing and Supply Agreement”). Pursuant to the Lonza Commercial Manufacturing and Supply Agreement, Lonza will (i) construct and build out a dedicated suite (the “Suite”) at Lonza’s facilities in Visp, Switzerland to manufacture certain key components (including drug substance) for our proprietary PCV franchise and any other products or intermediates we may choose (collectively, the “Products”) and (ii) maintain and operate the Suite (utilizing Lonza’s employees) to manufacture the Products as a service provided to us, including conducting related quality control and quality assurance operations. Lonza will be a preferred, non-exclusive, supplier of the Products to us, and we retain the right to procure the Products from one or more alternate and/or backup manufacturers of the Products (including at our own facilities).

Under the Lonza Commercial Manufacturing and Supply Agreement, prior to completion of construction and certification of the Suite for commercial operation, we will contribute to the capital expenditure costs to construct the Suite (and will own certain equipment in the Suite to be purchased or otherwise acquired by us), and will pay Lonza a fixed-rate monthly service fee for Lonza’s pre-commercial services prior to commencement of commercial operations (which monthly service fee amount is subject to increases in subsequent years). Following commencement of commercial operations of the Suite to manufacture the Products, we will pay Lonza (i) Suite fees based on allocations of certain of Lonza’s costs to maintain the facility in which the Suite is located and to provide shared services to us and Lonza’s other customers in such facility, (ii) service fees based upon Lonza’s actual full-time equivalent employee (“FTE”) costs to operate the Suite to manufacture the Products, and (iii) certain other pass-through costs, including for raw materials. In addition, we may be obligated to pay or reimburse Lonza for certain other fees and expenses under the Lonza Commercial Manufacturing and Supply Agreement. Lonza will be eligible for certain financial bonuses, and subject to certain financial penalties, as incentives for the timely completion of certain scale-up activities, receipt of certain regulatory approvals for the Suite and manufacture of the Products in accordance with our commercial requirements.

107

Table of Contents

Effective Date, we paid Lonza a repurposing fee (the “Repurposing Fee”) of CHF 27.0 million that will be credited back to us over a 10-year period starting upon commencement of commercial production.

2026 Development and Manufacturing Services Agreement

On February 18, 2026, we entered into a development and manufacturing services agreement with Lonza, effective as of January 1, 2026, pursuant to which Lonza will perform manufacturing process development and commercial manufacture and supply of certain key components for our proprietary PCV franchise. Under the agreement, we will pay Lonza for development and manufacturing services, in addition to paying for certain raw material and other costs. We will be required to purchase, and Lonza will be required to supply, the components pursuant to the relevant purchase orders under the agreement. In consideration of the commercial supply services and Lonza’s other obligations under the agreement, we will pay Lonza a daily fee for Lonza’s operation of the facility solely to actively manufacture the components. With respect to such commercial supply, and subject to termination rights, we and Lonza have agreed to a mutually binding percentage of annual facility capacity that shall be utilized by Lonza fully and exclusively for Lonza’s performance of services thereunder, which percentages may be adjusted under certain circumstances.

Unless earlier terminated, the agreement will remain in effect until December 31, 2038, subject to automatic renewal for up to three additional renewal periods of five years each, unless we elect not to renew. We may terminate the agreement for convenience, and the agreement contains customary for-cause termination rights for each party. If the Agreement is terminated (i) by us for convenience, or (ii) by Lonza for our uncured failure to pay material, undisputed amounts of money due to Lonza, then we shall pay Lonza certain cancellation fees as specified in the agreement.

Sutro Biopharma

Amended and Restated License Agreement

We are party to an amended and restated license agreement with Sutro Biopharma, dated October 12, 2015, which was subsequently amended on May 9, 2018, May 29, 2018, September 28, 2023 and November 21, 2023 (as amended, the “Sutro Biopharma License Agreement”). Under the Sutro Biopharma License Agreement, we received an exclusive, worldwide, royalty-bearing, sublicensable license under Sutro Biopharma’s patents and know-how relating to cell-free expression of proteins to (i) research, develop, use, sell, offer for sale, export, import and otherwise exploit specified vaccine compositions, such rights being sublicensable, for the treatment or prophylaxis of infectious diseases, excluding cancer vaccines, and (ii) manufacture, or have manufactured by an approved contract manufacturing organization, such vaccine compositions from extracts supplied by Sutro Biopharma pursuant to the Sutro Biopharma Supply Agreement (as described below). We are obligated to use commercially reasonable efforts to develop, obtain regulatory approval for and commercialize the vaccine compositions. In consideration of the rights granted under the Sutro Biopharma License Agreement, we are obligated to pay Sutro Biopharma a 4% royalty on worldwide aggregate annual net sales of our vaccine products for human health and a 2% royalty on such net sales of vaccine products for animal health. Such royalty rates are subject to specified reductions, including standard reductions for third-party payments and for expiration of relevant patent claims. We are also obligated to pay Sutro Biopharma any royalties due to Stanford University (the upstream licensor of Sutro Biopharma), to the extent the royalties payable by Sutro Biopharma to Stanford University are greater than the royalties payable by us to Sutro Biopharma. Royalties are payable on a vaccine composition-by-vaccine composition and country-by-country basis until the later of expiration of the last valid claim in the licensed patents covering such vaccine composition in such country and 10 years after the first commercial sale of such vaccine composition. The latest expiration date of a licensed Sutro Biopharma patent application, if issued, would be 2036, subject to any adjustment or extension of patent term that may be available in a particular country. In addition, we are obligated to pay Sutro Biopharma a percentage of net sublicensing revenue received in the low teen percentages. In addition, in the event we sublicense our non-manufacturing rights under the Sutro Biopharma License Agreement before a specified date, we are obligated to pay Sutro Biopharma a percentage, in the low double-digits, of the sublicensing revenue we receive under such agreement.

On September 28, 2023, we and Sutro Biopharma amended certain terms of the Sutro Biopharma License Agreement, including with respect to (i) royalty reduction provisions applicable in the event of expiration of relevant patent claims, which would result in lower royalties payable by us to Sutro Biopharma under certain circumstances, (ii) the ownership, prosecution, maintenance and enforcement of certain intellectual property rights licensed or arising under the Sutro Biopharma License Agreement (including as agreed to be amended in the Option Agreement (as defined below)), and (iii) the timing and form for financial reporting of royalty payment calculations.

The Sutro Biopharma License Agreement will remain in effect until terminated. The agreement may be terminated by either party for the other party’s material breach uncured within 60 days’ notice, by us at will with 60 days’ notice, or by Sutro Biopharma if we challenge Sutro Biopharma’s patents or if we undergo a change of control with a specified competitor of Sutro Biopharma.

108

Table of Contents

Supply Agreement

In May 2018, we entered into a supply agreement with Sutro Biopharma, which was subsequently amended on February 22, 2021 and November 21, 2023 (as amended, the “Sutro Biopharma Supply Agreement”) pursuant to which we purchase from Sutro Biopharma extract and custom reagents for use in manufacturing non-clinical and certain clinical supply of vaccine compositions utilizing the technology licensed under the Sutro Biopharma License at prices not to exceed a specified percentage above Sutro Biopharma’s fully burdened manufacturing cost. If any extracts or custom reagents do not meet the specifications and warranties provided, then we will not have an obligation to pay for the non-conforming product, and Sutro Biopharma will be obligated to replace the non-conforming product within the shortest possible time with conforming product at our cost. The term of the Sutro Biopharma Supply Agreement is from execution until the later of (i) July 31, 2022, or (ii) the date that we and Sutro Biopharma enter into the Phase 3/Commercial Supply Agreement and Sutro Biopharma is supplying to us each Product under the Phase 3/Commercial Supply Agreement (each term as defined in the Sutro Biopharma Supply Agreement). The Sutro Biopharma Supply Agreement may be terminated by either party for the other party’s material breach uncured within 60 days’ notice, by us at will with 60 days’ notice, or by mutual agreement of the parties. In December 2019, we exercised our right to require Sutro Biopharma to establish a second supplier for extract and custom reagents to support our anticipated clinical and commercial needs.

Option Agreement

In December 2022, we entered into an option grant agreement with Sutro Biopharma (the “Option Agreement”). Pursuant to the Option Agreement, we acquired from Sutro Biopharma (i) authorization to enter into an agreement with an independent alternate contract manufacturing organization (“CMO”) to directly source Sutro Biopharma’s cell-free extract, allowing us to have direct oversight over financial and operational aspects of the relationship with the CMO; and (ii) a right, but not an obligation, to obtain certain exclusive rights to internally manufacture and/or source extract from certain CMOs and the right to independently develop and make improvements to extract (including the right to make improvements to the extract manufacturing process as well as cell lines) for use in connection with the exploitation of certain vaccine compositions (the “Option”). We and Sutro Biopharma agreed to negotiate the terms and conditions of a form definitive agreement to be entered into in the event we exercise the Option, which would include the terms and conditions set forth in an executed term sheet between us (the “Term Sheet”) and such terms that were necessary to give effect to each of the terms and conditions set forth in the Term Sheet (the “Form Definitive Agreement”).

As consideration for the Option and other rights and authorizations granted to us under the Option Agreement, we paid Sutro Biopharma upfront consideration of $22.5 million, consisting of (i) $10.0 million in cash and $7.5 million worth of shares of our common stock (the number of shares calculated based on the arithmetic average of the daily volume weighted average price of our common stock as traded on Nasdaq in the three consecutive trading days immediately prior to the issuance thereof) in December 2022, and (ii) $5.0 million in October 2023 within five business days after we and Sutro Biopharma mutually agree in writing upon the Form Definitive Agreement on September 28, 2023. The 167,780 shares of common stock issued was recorded at fair value of $8.0 million on the date of settlement, December 22, 2022.

On November 21, 2023 (the “Option Exercise Date”), we exercised the Option by submitting written notice thereof to Sutro Biopharma and concurrently paid Sutro Biopharma $50.0 million in cash as the first of two installment payments for the Option exercise price, followed by the second and final installment of $25.0 million in cash in May 2024. We determined there was no current alternative future use of the acquired manufacturing rights from the Option Agreement and, as a result, the amounts paid were expensed as incurred. Upon the occurrence of certain regulatory milestones, certain additional milestone payments may total up to $60.0 million in cash. In the event that we undergo a change of control, certain rights and payments may be accelerated.

Manufacturing Rights Agreement

Concurrent with the payment of the first installment of the Option exercise price pursuant to the Option Agreement, on November 21, 2023, the manufacturing rights agreement (in the form of the Form Definitive Agreement) between us and Sutro Biopharma (the “Manufacturing Rights Agreement”) became effective. Under the Manufacturing Rights Agreement, we received an exclusive (except as to Sutro Biopharma), perpetual (subject to termination), worldwide license, for no additional royalty (i.e., royalty-free, other than any royalties due under the Sutro Biopharma License Agreement), under Sutro Biopharma’s relevant patents and know-how, to manufacture or have manufactured extract and improvements to extract (in any form) solely for use in the research, development, use, production, sale, offering for sale, export, import, commercialization or other exploitation of Vaccine Compositions (as defined in the Sutro Biopharma License Agreement) as well as certain rights with respect to certain regulatory matters related to extract and its use in connection with such Vaccine Compositions. We have the right to extend our rights and obligations under the Manufacturing Rights Agreement to our affiliates and to sublicense our rights to manufacture extract and improvements to extract to certain third-party CMOs and other contractors (for our benefit and not for such third party’s independent commercial use). For clarity, we are

109

Table of Contents

not permitted to manufacture extract for sale to third parties for the independent use of such third parties. Under the Manufacturing Rights Agreement, we have the obligation to protect the confidentiality of the extract manufacturing technology, and Sutro Biopharma has certain audit rights in connection therewith.

Under the Manufacturing Rights Agreement, upon our request and at our cost, Sutro Biopharma will support up to two technology transfers to us (or to an affiliate of ours or certain third-party CMOs designated by us) of certain Sutro Biopharma know-how, materials and information to enable us to manufacture or have manufactured extract. Under certain circumstances, Sutro Biopharma may source extract from us or certain third-party CMOs, subject to reimbursement for technology transfer costs.

The Manufacturing Rights Agreement contains certain terms with respect to the ownership, prosecution, maintenance and enforcement of certain intellectual property rights licensed or arising under the Manufacturing Rights Agreement, which are generally consistent with the Sutro Biopharma License Agreement.

Unless earlier terminated, the Manufacturing Rights Agreement will remain in effect in perpetuity. Sutro Biopharma may only terminate the Manufacturing Rights Agreement in the event of our (i) uncured, intentional, material breach of certain confidentiality provisions resulting in actual, material harm to Sutro Biopharma’s business, (ii) uncured, intentional material breach of certain provisions relating to the use of certain of Sutro Biopharma’s know-how outside of the Vaccine Field, (iii) unintentional, material breach of certain provisions relating to the use of certain of Sutro Biopharma’s know-how outside of the Vaccine Field that we do not use reasonable best efforts to cease and (to the extent reasonably curable) cure in a timely fashion, or (iv) uncured failure to pay the Option exercise price or any undisputed milestone payment under the Option Agreement when due. We may terminate the Manufacturing Rights Agreement at our discretion upon 60 days’ written notice, and both parties may terminate the Manufacturing Rights Agreement upon mutual written consent.

Thermo Fisher Scientific

Commercial Manufacturing and Supply Agreement

On September 24, 2025, we entered into a master services agreement with Patheon Manufacturing Services LLC, part of Thermo Fisher Scientific (collectively, “Thermo Fisher”), pursuant to which Thermo Fisher will formulate, fill, inspect, package, label, test, manufacture and supply drug product for us at Thermo Fisher's facility in Greenville, North Carolina (the "Thermo Fisher Commercial Manufacturing and Supply Agreement"). Pursuant to the Thermo Fisher Commercial Manufacturing and Supply Agreement, we have agreed to order drug product from Thermo Fisher based on certain binding forecast periods and established prices. In addition, we will also pay Thermo Fisher for technology transfer activities and reimburse Thermo Fisher for certain out-of-pocket capital expenditures under the terms of the agreement.

The Thermo Fisher Commercial Manufacturing and Supply Agreement has an initial term of 15 years and will automatically renew for additional three-year periods unless either party provides notice of non-renewal before the end of the then existing term, subject to completion of ongoing services. We are permitted to terminate the Thermo Fisher Commercial Manufacturing and Supply Agreement prior to expiration, subject to the payment of applicable termination fees, plus certain capital expenditure commitments.

Impact of Certain Trends and Macroeconomic Environment

We operate in an industry that is subject to significant government regulation. Our operations are subject to significant risk and uncertainties, including financial, operational, technological, regulatory and political risks. Such factors include, but are not necessarily limited to, the results of clinical testing and trial activities; our ability to adequately demonstrate sufficient safety, tolerability and immunogenicity or efficacy of our vaccine candidates; our ability to enroll subjects in our ongoing and future clinical trials; our ability to successfully manufacture and supply our vaccine candidates for clinical trials or for future potential commercialization; our ability to obtain additional capital to finance our operations; our ability to obtain, maintain and protect our intellectual property rights; developments relating to our competitors and our industry, including competing vaccine candidates; the ability to obtain regulatory approval; the necessary requirements for regulatory approval; the ability to obtain favorable licensing, manufacturing or other agreements; the political and regulatory environment; general and market conditions; and other risks and uncertainties, including those more fully described in the “Risk Factors” section of this Annual Report on Form 10-K.

The trends towards rising inflation may materially adversely affect our business and corresponding financial position and cash flows. Inflationary factors, such as increases in the cost of our clinical trial materials and supplies, fluctuating interest rates and increases in overhead costs may adversely affect our operating results. Fluctuating interest rates and rising inflation rates also present a challenge impacting the U.S. economy and could make it more difficult for us to obtain traditional financing on acceptable terms, if at all, in the future.

110

Table of Contents

We may experience increases in our operating costs in the near future, including our labor costs and research and development costs, due to rising inflation, tariffs, supply chain constraints, and civil and political unrest in certain countries and regions.

Components of Results of Operations

Operating Expenses

Research and Development

Research and development expenses represent costs incurred in performing research, development and manufacturing activities in support of our own product development efforts. Our research and development expenses include internal personnel-related costs (including salaries, employee benefits and stock-based compensation) for our personnel in research and development functions, and external costs including (i) product manufacturing costs, primarily related to acquiring, developing and manufacturing supplies for clinical trials and to prepare for potential future commercial launches, including fees paid to contract manufacturing organizations; (ii) clinical costs related to agreements with contract research organizations , investigative sites and consultants to conduct non-clinical and preclinical studies and clinical trials; (iii) research and development consumables, laboratory supplies and equipment costs; (iv) facility and other allocated shared services; and (v) other expenses primarily including professional and consulting services costs.

Our PCV programs include VAX-31, VAX-24 and VAX-XL, and our non-PCV programs include VAX-A1, VAX-GI, and other discovery-stage programs. In August 2025, we announced that we paused the advancement, beyond preclinical development, of VAX-A1 and VAX-GI while remaining confident in their potential and preserving the option to advance the programs in the future. The majority of our external costs relate to our PCV programs compared to the costs related to non-PCV programs. Most of the external costs associated with our vaccine candidates, particularly our PCV programs, are common in nature, and can be deployed across multiple candidates or redeployed as our vaccine development strategy evolves; as a result, we do not track external costs by candidate, program or project. We do not allocate internal personnel-related costs by program or project because several of our departments support multiple vaccine candidate programs and the hours are not tracked separately by program.

VAX-31 and VAX-24 are in the clinical stages, and VAX-XL and our non-PCV programs are in preclinical stages. The majority of our external costs relate to our clinical-stage programs compared to the costs related to our preclinical-stage programs. Costs associated with preclinical programs are relatively small and insignificant to the overall financial statements. Further, several expenses are shared among various vaccine programs and, as such, we do not separately track external costs by clinical and preclinical stages.

Research and development expenses, including costs related to acquired manufacturing rights, are expensed as incurred if it is determined there is no alternative future use. Non-refundable advance payments for services that will be used or rendered for future research and development activities are recorded as prepaid expenses and recognized as expenses as the related services are performed.

We expect our research and development expenses to increase in absolute dollars for the foreseeable future as we advance our vaccine candidates into and through preclinical studies and clinical trials, manufacture drug product for our clinical trials and to support the potential initial commercial launch of VAX-31 in the adult population, scale up our manufacturing activities, establish additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population, pursue regulatory approval of our vaccine candidates and expand our pipeline of vaccine candidates. The process of conducting the necessary preclinical and clinical research and completing the manufacturing requirements to obtain regulatory approval is costly and time-consuming. The actual probability of success for our vaccine candidates may be affected by a variety of factors, including the safety and efficacy or immunogenicity of our vaccine candidates, clinical data, investment in our clinical programs, competition, manufacturing capabilities and commercial viability. We may never succeed in achieving regulatory approval for any of our vaccine candidates. As a result of the uncertainties discussed above, we are unable to determine the duration and completion costs of our research and development projects or if, when and to what extent we will generate revenue from the commercialization and sale of our vaccine candidates.

111

Table of Contents

activity has been performed or when the goods have been received. We make significant judgments and estimates in determining accrued research and development liabilities as of each reporting period based on the estimated time period over which services will be performed and the level of effort to be expended. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or prepaid expense accordingly.

Although we do not expect our estimates to be materially different from amounts actually incurred, if our estimates of the status and timing of services performed differ from the actual status and timing of services performed, it could result in us reporting amounts that are too high or too low in any particular period.

Our research and development costs may vary significantly based on factors such as:

•the costs and timing of our CMC activities, including fulfilling good manufacturing practice (“GMP”) related standards and compliance, and identifying and qualifying second suppliers;

•the costs related to raw materials we purchase directly or through our third-party manufacturing and supply partners;

•the cost of clinical trials of our vaccine candidates;

•changes in the standard-of-care on which a clinical development plan was based, which may require new or additional trials;

•the number of sites included in the trials;

•the countries in which the trials are conducted;

•delays in adding a sufficient number of trial sites and recruiting suitable volunteers to participate in our clinical trials;

•the number of subjects that participate in the trials;

•the number of doses that subjects receive;

•subjects dropping out of a study or lost in follow-up;

•potential additional safety monitoring requested by regulatory agencies;

•the duration of subject participation in the trials and follow-up;

•the cost and timing of manufacturing our vaccine candidates;

•the phase of development of our vaccine candidates;

•the costs of establishing additional manufacturing capacity to meet potential incremental supply requirements following the potential commercial launches of VAX-31 in the adult population and VAX-31 or VAX-24 in the pediatric population;

•the costs that may be required for secondary supply sources; and

•the immunogenicity or efficacy and safety and tolerability profile of our vaccine candidates.

General and Administrative

General and administrative expenses consist primarily of costs and expenses related to personnel (including salaries, employee benefits and stock-based compensation) in our executive, legal, finance and accounting, human resources and other administrative functions; legal services relating to intellectual property and corporate matters; accounting, auditing, consulting and tax services; insurance; and facility and other allocated shared costs not otherwise included in research and development expenses. We expect our general and administrative expenses to continue to increase in absolute dollars for the foreseeable future as we increase our headcount and expand our services to support our continued research and development activities and grow our business.

112

Table of Contents

Other Income (Expense), Net

Other income (expense), net includes interest income earned from our cash, cash equivalents and investments, grant income and foreign currency transaction gains (losses) related to our Swiss Franc and Euro cash and liability balances, loss on disposals of fixed assets and interest expense.

Interest Income

Interest income is earned from our cash and cash equivalents balances and short- and long-term investments. The cost of investment securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in other income, net. Realized gains and losses are also included in other income, net. When the fair value of a debt security declines below its amortized cost basis, any portion of that decline attributable to credit losses, to the extent expected to be nonrecoverable before the sale of the security, is recognized in our consolidated statements of operations. When the fair value of a debt security declines below its amortized cost basis due to changes in interest rates, such amounts are recorded in other comprehensive loss, and are recognized in our consolidated statements of operations only if we sell or intend to sell the security before recovery of its cost basis.

Grant Income

Our vaccine development program for VAX-A1, a novel conjugate vaccine candidate designed to prevent disease caused by Group A Streptococcus, has been funded in part by a grant obtained from Combating Antibiotic Resistant Bacteria Biopharmaceutical Accelerator (“CARB-X”), a global non-profit partnership dedicated to accelerating antibacterial innovation to tackle the rising global threat of drug-resistant bacteria. The CARB-X grant provided funding of $11.7 million upon the achievement of VAX-A1 development milestones through June 2024. As of the second quarter of 2024, all of these milestones had been successfully achieved, and no further amounts will be funded under this CARB-X grant.

Our vaccine development program for VAX-GI, a novel preclinical vaccine candidate being developed as a preventative treatment for dysentery and shigellosis, which is caused by Shigella bacteria, is currently funded in part by two grants obtained from the NIH administered by the University of Maryland, Baltimore. Our first grant from the NIH was awarded in April 2021 and provides for potential funding up to five years totaling approximately $0.5 million. In June 2023, we received another grant from the NIH that provides for potential funding up to five years totaling approximately $4.6 million. As of December 31, 2025, we have received and expect to continue to receive funding under each of these grants.

We are currently working on a discovery program with the University of North Carolina at Chapel Hill and the University of Chicago to develop a vaccine candidate for the prevention of Chlamydia, which is funded in part by a grant from the NIAID that provides potential funding up to five years totaling approximately $9.5 million. As of December 31, 2025, we have received and expect to continue to receive funding under this grant.

Income from grants is recognized in the period during which the related specified expenses are incurred, provided

that the conditions under which the grants were provided have been met. We recognized $0.5 million, $1.0 million and $4.8 million in grant income for funding research and development under these awards during the years ended December 31, 2025, 2024 and 2023, respectively. Grant income is included as a component of Other income, net in the consolidated statements of operations.

113

Table of Contents

Results of Operations

The following table summarizes our results of operations for the periods presented:

(in thousands)

Operating expenses:

Other income, net:

Operating Expenses

Research and Development Expenses

(in thousands)

External costs:

Internal costs:

Research and development expenses increased by $317.7 million, or 66.6%, in 2025 compared to 2024. The increase was driven by external costs, which grew by $251.2 million largely due to increased development and manufacturing activities in connection with the adult and infant PCV programs, including to support the potential future commercial launches. Product manufacturing costs increased by $229.9 million, clinical trials related expenses increased by $17.3 million, facility and other allocated expenses increased by $6.8 million, and other external costs increased by $5.2 million compared to the prior period which, were partially offset by a $8.0 million decrease in research expenses. The increase in research and development expenses was further driven by internal personnel-related costs, which grew by $66.5 million largely due to headcount growth.

Acquired Manufacturing Rights

In November 2023, we exercised the Option by submitting written notice thereof to Sutro Biopharma and concurrently paid Sutro Biopharma $50.0 million in cash as the first of two installment payments for the Option exercise price, followed by the second and final installment of $25.0 million in cash in May 2024. We determined there was no current alternative future use of the acquired manufacturing rights from the Option Agreement and, as a result, the amounts paid were expensed as incurred in the year ended December 31, 2023. No additional costs were incurred in the years ended December 31, 2025 or 2024.

114

Table of Contents

Upon the occurrence of certain regulatory milestones, we would be obligated to pay Sutro Biopharma certain additional milestone payments totaling up to $60.0 million in cash. In the event that we undergo a change of control, certain rights and payments may be accelerated.

General and Administrative Expenses

General and administrative expenses increased by $36.5 million, or 39.3%, in 2025 compared to 2024. The increase was due to primarily (i) personnel-related costs, which grew by $25.8 million largely due to headcount growth, (ii) professional and consulting services, which grew by $6.2 million, and (iii) a $3.0 million increase in facility and other allocated expenses.

Other Income, Net

Other income, net increased by $51.4 million , or 48.7%, in 2025 compared to 2024. The increase was primarily attributable to a $42.7 million increase in unrealized and realized foreign currency gains due to the weakening of the U.S. Dollar relative to the Swiss Franc. Additionally, interest income increased by $9.7 million which was driven by (i) higher average cash and investment balances in the year ended December 31, 2025 as a result of proceeds from our follow-on equity and ATM financings during the year ended December 31, 2024 and (ii) an increased average duration of our investment portfolio in the year ended December 31, 2025.

Liquidity and Capital Resources

From inception through December 31, 2025, we have incurred losses and negative cash flows from operations and have funded our operations primarily through the issuance of common stock, pre-funded warrants to purchase our common stock and, prior to our IPO, redeemable convertible preferred stock, totaling approximately $4.7 billion in aggregate gross proceeds or $4.5 billion net of underwriting discounts, commissions and offering expenses. As of December 31, 2025, we had $174.0 million of cash and cash equivalents, $2,268.7 million in investments and an accumulated deficit of $2,154.9 million.

On July 2, 2021, we filed a shelf registration statement on Form S-3ASR (the “2021 Shelf Registration Statement”) under which we could, from time to time, sell securities in one or more offerings of our common stock, preferred stock, debt securities or warrants. The 2021 Shelf Registration Statement became automatically effective upon the filing of the Form S-3ASR on July 2, 2021, and was scheduled to expire on July 2, 2024. In anticipation of such expiration, we filed a new shelf registration statement on Form S-3ASR on May 24, 2024 solely to replace the 2021 Shelf Registration Statement (such replacement registration statement, the “2024 Shelf Registration Statement”). Pursuant to the 2024 Shelf Registration Statement, we may, from time to time, sell securities in one or more offerings of our common stock, preferred stock, debt securities or warrants. The 2024 Shelf Registration Statement became automatically effective upon the filing of the Form S-3ASR on May 24, 2024.

ATM Program

In July 2021, we entered into an Open Market Sales AgreementSM (the “Original ATM Sales Agreement”) with Jefferies LLC (“Jefferies”), which provided that, upon the terms and subject to the conditions and limitations set forth in the Original ATM Sales Agreement, we had the right to issue and sell, from time to time, shares of our common stock having an aggregate offering price of up to $150.0 million through Jefferies acting as our sales agent or principal. As of February 27, 2023, we had sold 4,995,709 shares of our common stock under the Original ATM Sales Agreement at a weighted average price of $27.57 per share for aggregate gross proceeds of $137.8 million. On February 27, 2023, we and Jefferies entered into an amendment to the Original ATM Sales Agreement (as amended, the “Amended ATM Sales Agreement”) pursuant to which we may offer and sell shares of our common stock having an aggregate offering price of up to $400.0 million. The material terms and conditions of the Original ATM Sales Agreement otherwise remain unchanged. We will pay Jefferies a commission of up to 3.0% of the gross sales proceeds of any common stock sold through Jefferies under the Amended ATM Sales Agreement; however, we are not obligated to make any sales of common stock. As of December 31, 2025, we have sold 4,211,367 shares of our common stock under the Amended ATM Sales Agreement at a weighted average price of $64.19 per share for aggregate gross proceeds of $270.3 million ($264.2 million net of commissions and offering expenses) with $129.7 million remaining for future sales under the Amended ATM Sales Agreement. We have made no sales under the Amended ATM Sales Agreement since August 2024.

Underwritten Follow-on Public Offerings

In January 2022, we completed an underwritten public offering in which we issued 2,500,000 shares of common stock at a price of $20.00 per share and pre-funded warrants to purchase 2,500,000 shares of our common stock at a price of $19.999

115

Table of Contents

per underlying share. In February 2022, the underwriters exercised their option to purchase an additional 750,000 shares of common stock. In aggregate, we received $107.6 million in net proceeds after deducting underwriting discounts and commissions and other offering expenses payable by us, and excluding the exercise of any pre-funded warrants.

In October 2022, we completed an underwritten public offering of 17,812,500 shares of our common stock, which included the full exercise of the underwriters' option to purchase an additional 2,812,500 shares, at a price of $32.00 per share and pre-funded warrants to purchase 3,750,000 shares of our common stock at a price of $31.999 per underlying share. In aggregate, we received $651.6 million in net proceeds after deducting underwriting discounts and commissions and other offering expenses payable by us, and excluding the exercise of any pre-funded warrants.

In April 2023, we completed an underwritten public offering of 13,030,000 shares of our common stock, which included the full exercise of the underwriters’ option to purchase an additional 1,830,000 shares, at a price of $41.00 per share and pre-funded warrants to purchase 1,000,000 shares of our common stock at a price of $40.999 per underlying share. In aggregate, we received $545.3 million in net proceeds after deducting underwriting discounts and commissions and other estimated offering expenses payable by us, and excluding the exercise of any pre-funded warrants.

In February 2024, we completed an underwritten public offering of 12,695,312 shares of our common stock, which included the full exercise of the underwriters’ option to purchase an additional 1,757,812 shares, at a price of $64.00 per share and pre-funded warrants to purchase 781,250 shares of our common stock at a price of $63.999 per underlying share. In aggregate, we received $816.5 million in net proceeds after deducting underwriting discounts and commissions and other estimated offering expenses payable by us, and excluding the exercise of any pre-funded warrants.

In September 2024, we completed an underwritten public offering of 12,087,378 shares of our common stock, which included the full exercise of the underwriters’ option to purchase an additional 1,893,203 shares, at a price of $103.00 per share and pre-funded warrants to purchase 2,427,184 shares of our common stock at a price of $102.999 per underlying share. In aggregate, we received $1.4 billion in net proceeds after deducting underwriting discounts and commissions and other offering expenses payable by us, and excluding the exercise of any pre-funded warrants.

The pre-funded warrants are exercisable, at the option of each holder, in whole or in part by delivering to us a duly executed exercise notice and payment of the exercise price. No fractional shares of common stock will be issued in connection with the exercise of a pre-funded warrant. The holders of the pre-funded warrants may also satisfy their obligation to pay the exercise price through a “cashless exercise,” in which the holder receives the net value of the pre-funded warrant in shares of common stock determined according to the formula set forth in the pre-funded warrant.

The pre-funded warrants will not expire until they are fully exercised. However, we may not effect the exercise of any pre-funded warrants, and a holder will not be entitled to exercise any portion of any pre-funded warrants that, upon giving effect to such exercise, would cause: (i) the aggregate number of shares of our common stock beneficially owned by such holder (together with affiliates) to exceed 4.99% or 9.99% of the number of shares of our common stock outstanding immediately after giving effect to the exercise, as applicable; or (ii) the combined voting power of our securities beneficially owned by such holder (together with its affiliates) to exceed 4.99% or 9.99% of the combined voting power of all of our securities outstanding immediately after giving effect to the exercise, as applicable, as such percentage ownership is determined in accordance with the terms of the pre-funded warrants. However, any holder of a pre-funded warrant may increase or decrease such percentage to any other percentage not in excess of 19.99% upon at least 61 days' prior notice for the holder to us.

In January 2025, 1,000,000 shares and 2,500,000 shares underlying the pre-funded warrants from the January 2022 and October 2022 offerings, respectively, were exercised to receive 999,988 shares and 2,499,971 shares of common stock, net of exercise costs, respectively. In June 2025, 640,705 shares underlying pre-funded warrants from the February 2024 offering were exercised to receive 640,685 shares of common stock, net of exercise costs. In October 2025, 853,936 shares underlying pre-funded warrants from the February 2024 and September 2024 offering were exercised to receive 853,914 shares of common stock, net of exercise costs. As of December 31, 2025, no other shares underlying the pre-funded warrants have been exercised.

In February 2026, we completed an underwritten public offering of 12,650,000 shares of our common stock, which included the full exercise of the underwriters' option to purchase an additional 1,650,000 shares, at a price of $50.00 per share. In aggregate, we received approximately $600.2 million in net proceeds after deducting underwriting discounts and commissions and other estimated offering expenses payable by us.

116

Table of Contents

Future Funding Requirements

Our primary uses of cash are to fund our operations, which consist primarily of research, development and manufacturing expenditures related to our programs and, to a lesser extent, capital expenditures for our commercial manufacturing facility build-out and general and administrative expenditures. We anticipate that we will continue to incur significant expenses and capital expenditures for the foreseeable future as we continue to advance our vaccine candidates, expand our corporate infrastructure, further our research and development initiatives for our vaccine candidates, build out and operate our commercial manufacturing facilities, and scale our laboratory and manufacturing operations. We are subject to all of the risks typically related to the development of new drug candidates, and we may encounter unforeseen expenses, difficulties, complications, delays and other unknown factors that may adversely affect our business. We anticipate that we will need substantial additional funding in connection with our continuing operations.

We believe that our existing cash, cash equivalents and investments as of the date of this Annual Report on Form 10-K will be sufficient to fund our operating expenses and capital expenditure requirements through at least 12 months from the filing date of this Annual Report on Form 10-K. We have raised substantial capital; however, we will need to raise substantial additional capital to complete development, manufacturing and commercialization of our drug candidates. Until we can generate sufficient revenue from the commercialization of our vaccine candidates or from collaboration agreements with third parties, if ever, we expect to finance our future cash needs through public or private equity or debt financings, third-party (including government) funding and marketing and distribution arrangements, as well as other collaborations, strategic alliances and licensing arrangements, or any combination of these approaches. The sale of equity, pre-funded warrants or convertible debt securities may result in dilution to our stockholders and, in the case of preferred equity securities or convertible debt, those securities could provide for rights, preferences or privileges senior to those of our common stock. Debt financings may subject us to covenant limitations or restrictions on our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Our ability to raise additional funds may be adversely impacted by deteriorating global economic conditions, including higher inflation rates and changes in interest rates, and the recent disruptions to and volatility in the credit and financial markets in the United States and worldwide. There can be no assurance that we will be successful in acquiring additional funding at levels sufficient to fund our operations or on terms favorable or acceptable to us. If we are unable to obtain adequate financing when needed or on terms favorable or acceptable to us, we may be forced to delay, reduce the scope of or eliminate one or more of our research and development programs.

Our future capital requirements will depend on many factors, including:

•the timing, scope, progress, results and costs of research and development, testing, screening, manufacturing, preclinical development and clinical trials;

•the outcome, timing and cost of seeking and obtaining regulatory approvals from the FDA and comparable foreign regulatory authorities, which may require more studies than those that we currently expect or change their requirements regarding the data required to support a marketing application;

•the cost of building a sales force in anticipation of any product commercialization;

•the costs of future commercialization activities, including product manufacturing, marketing, sales, royalties and distribution, for any of our vaccine candidates for which we receive marketing approval;

•our ability to maintain existing, and establish new, strategic collaborations, licensing or other arrangements and the financial terms of any such agreements, including the timing and amount of any future milestone, royalty or other payments due under any such agreement;

•exchange rate fluctuations due to exposure of foreign operations and foreign currency fluctuations and translations;

•any product liability or other lawsuits related to our products;

•the revenue, if any, received from commercial sales, or sales to foreign governments, of our vaccine candidates for which we may receive marketing approval;

117

Table of Contents

•the costs to establish, maintain, expand, enforce and defend the scope of our intellectual property portfolio, including the amount and timing of any payments we may be required to make, or that we may receive, in connection with licensing, preparing, filing, prosecuting, defending and enforcing our patents or other intellectual property rights;

•expenses needed to attract, hire and retain skilled personnel; and

•the impact of macroeconomic factors, including potential effects of changes in federal government regulation, rising inflation which may impact labor costs, research and development costs, tariffs, and supply chain constraints, as well as civil and political unrest in certain countries and regions, which may exacerbate the magnitude of the factors discussed above.

A change in the outcome of any of these or other variables could significantly change the costs and timing associated with the development of our vaccine candidates. Furthermore, our operating plans may change in the future, and we may need additional funds to meet operational needs and capital requirements associated with such change.

Cash Flows

The following table summarizes our cash flows for the periods indicated:

Year Ended December 31,

(in thousands)

Effect of exchange rate changes on cash and cash equivalents 2,439 426 (6,686)

Net Cash Flows from Operating Activities

Cash used in operating activities for the year ended December 31, 2025 was $655.6 million, an increase of $203.0 million compared to 2024. The increase was primarily due to higher cash expenditures to support our business growth and increased development and manufacturing activities in connection with the adult and infant PCV programs, including support for the potential future commercial launches. The increase in cash used was partially offset by the timing of payments for manufacturing and accrued expenses in 2025.

Net Cash Flows from Investing Activities

Cash provided by investing activities for the year ended December 31, 2025 was $437.4 million, an increase of $2,443.0 million compared to 2024. The increase was primarily due to decreases of $1,875.2 million in investment purchases and $53.5 million in payments related to manufacturing facility build-out and equipment construction-in-progress compared to 2024, partially offset by a $397.9 million increase in proceeds from maturities of investments and a $107.7 million increase in sales of investments in 2025.

Net Cash Flows from Financing Activities

Cash provided by financing activities for the year ended December 31, 2025 was $2.0 million, a decrease of $2,446.5 million compared to 2024. The decrease was primarily due to a decrease in (i) net proceeds from our follow-on public offerings of $2,239.7 million, (ii) net proceeds from the Amended ATM Sales Agreement of $195.9 million, and (iii) proceeds from the issuance of shares through employee equity incentive plans of $14.1 million, partially offset by a decrease in taxes paid related to the net share settlement of equity awards of $3.3 million.

Contractual Obligations and Commitments

Our material cash requirements include the following contractual and other obligations.

118

Table of Contents

Leases

We have operating lease agreements for our office spaces. As of December 31, 2025, we had lease payment obligations totaling $164.2 million, of which $12.1 million is payable within one year.

Option Agreement

On November 21, 2023 (the “Option Exercise Date”), we exercised the Option pursuant to the Option Agreement by submitting written notice thereof to Sutro Biopharma and concurrently paid Sutro Biopharma $50.0 million in cash as the first of two installment payments for the Option exercise price, followed by the second and final installment of $25.0 million in cash on May 13, 2024. Upon the occurrence of certain regulatory milestones, we would be obligated to pay Sutro Biopharma certain additional milestone payments totaling up to $60.0 million in cash. In the event that we undergo a change of control, certain rights and payments may be accelerated.

Purchase Commitments

We have certain payment obligations under various license agreements. Under these agreements, we are required to make milestone payments upon successful completion and achievement of certain intellectual property, clinical, regulatory and sales milestones. The payment obligations under the license agreements are contingent upon future events such as our achievement of specified development, clinical, regulatory and commercial milestones, and we will be required to make development milestone payments and royalty payments in connection with the sale of products developed under these agreements. As the achievement and timing of these future milestone payments are not probable or estimable, such amounts have not been included in our balance sheets as of December 31, 2025.

We enter into agreements in the normal course of business with CMOs and other vendors for manufacturing services and raw materials purchases. We rely on several third-party manufacturers for our manufacturing requirements. As of December 31, 2025, we had the following amounts of non-cancelable purchase commitments related to manufacturing services and raw materials purchased due to our key manufacturing partners. These amounts represent our minimum contractual obligations, including termination fees. If we terminate certain firm orders with our key manufacturing partners, we will be required to pay for the manufacturing services scheduled or raw materials purchased under our arrangements. The actual amounts we pay in the future to the vendors under such agreements may differ from the purchase order amounts.

Years ending December 31, (in thousands)

Thereafter —

Critical Accounting Policies and Significant Judgments and Estimates

Our management’s discussion and analysis of our financial condition and results of operations are based on our consolidated financial statements, which have been prepared in accordance with accounting principles generally accepted in the United States of America. The preparation of these consolidated financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities in our consolidated financial statements. On an ongoing basis, we evaluate our estimates and judgments, including those related to accrued research and development expenses, stock-based compensation and leases. We base our estimates on historical experience, known trends and events and various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in the notes to our consolidated financial statements included elsewhere in this Annual Report on Form 10-K, we believe that the following critical accounting policies are most important to understanding and evaluating our reported financial results:

119

Table of Contents

Accrued Research and Development Expenses

We have entered into various agreements with CMOs and CROs. As part of the process of preparing our consolidated financial statements, we are required to estimate our accrued research and development expenses, including accrued contract manufacturing expenses, as of each balance sheet date. This process involves reviewing open contracts and purchase orders, communicating with our personnel and third parties to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of the actual cost. We make estimates of our accrued research and development expenses as of each balance sheet date based on facts and circumstances known to us at that time. We periodically confirm the accuracy of our estimates with the service providers and make adjustments, if necessary. The significant estimates in our accrued research and development expenses include the costs incurred for services performed by our vendors in connection with research and development activities for which we have not yet been invoiced.

We accrue for costs related to research and development activities based on our estimates of the services received and efforts expended pursuant to quotes and contracts with vendors, including CMOs and CROs, that conduct research, development and manufacturing on our behalf. The financial terms of these agreements are subject to negotiation, vary from contract to contract and may result in uneven payment flows. There may be instances in which payments made to our vendors will exceed the level of services provided and result in a prepayment of the research and development expense. Advance payments for goods and services that will be used in future research and development activities are expensed when the activity has been performed or when the goods have been received. We make significant judgments and estimates in determining accrued research and development liabilities as of each reporting period based on the estimated time period over which services will be performed and the level of effort to be expended. If the actual timing of the performance of services or the level of effort varies from our estimate, we adjust the accrual or prepaid expense accordingly.

Stock-Based Compensation Expense

Our use of the Monte Carlo simulation model and Black-Scholes option-pricing model requires the input of subjective assumptions, such as expected volatility. In addition to expected volatility, the assumptions, including expected term and risk-free interest rate, used in our option pricing model and simulation model represent management’s best estimates. These estimates involve inherent uncertainties and the application of management’s judgment. If factors change and different assumptions are used, our stock-based compensation expense could be materially different in the future.

Refer to Note 2, “Basis of Presentation and Summary of Significant Accounting Policies,” and Note 10, “Equity Incentive Plans,” to our consolidated financial statements included in Part II, Item 8 of this Annual Report on Form 10-K for more information on assumptions used in estimating stock-based compensation expense.

Recently Adopted Accounting Pronouncements

See Note 2, “Basis of Presentation and Summary of Significant Accounting Policies,” to our consolidated financial statements included in Part II, Item 8 of this Annual Report on Form 10-K for additional information.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Interest Rate Risk

Our cash and cash equivalents as of December 31, 2025 and 2024 consisted of readily available checking and money market funds. As of December 31, 2025, we also invested in U.S. Treasury securities, U.S. government agency securities, corporate debt, commercial paper and asset-backed securities. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates. We do not believe that our cash and cash equivalents have significant risk of default or illiquidity. As of December 31, 2025 and 2024, we had approximately $2,442.6 million and $3,134.7 million in cash, cash equivalents and investments, respectively. For the years ended December 31, 2025 and 2024, we had interest income of $119.7 million and $110.0 million, respectively. The following

120

Table of Contents

table shows the impact of a hypothetical 10% increase or decrease in interest rates on our net assets as of December 31, 2025 and our net loss for the year then ended:

Hypothetical Change in Interest Rates (in thousands)

Concentrations of Credit Risk

Financial instruments that potentially subject us to a concentration of credit risk consist primarily of cash, cash equivalents and investments. We invest in money market funds, U.S. Treasury securities, U.S. government agency securities, corporate debt, commercial paper and asset-backed securities. We maintain bank deposits in federally insured financial institutions and these deposits may exceed federally insured limits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash and issuers of investments to the extent recorded on the consolidated balance sheets. Our investment policy limits investments to money market funds, certain types of debt securities issued by the U.S. Government and its agencies, corporate debt, commercial paper and asset-backed securities, and places restrictions on the credit ratings, maturities and concentration by type and issuer. We believe that our exposure to credit risks is not significant and that a hypothetical 10% change in credit rates would not have a significant impact on our portfolio.

Foreign Currency Risk

We are exposed to market risk related to changes in foreign currency exchange rates, mainly relating to our contracts with Lonza, our CMO in Switzerland. We have also entered into a limited number of contracts with other parties with payments denominated in foreign currencies. Payments under these contracts are made in foreign currencies and are subject to fluctuations in foreign currency rates. We do not currently have a formal program in place to hedge foreign currency risks. However, from time to time, we buy Swiss Francs (“CHF”), which is the majority of our foreign currency exposure, at market and hold CHF in our bank accounts. As of December 31, 2025, we had approximately $38.9 million of CHF cash and cash equivalents held at three financial institutions. As of December 31, 2024, we had approximately $25.8 million of CHF cash and cash equivalents held at two financial institutions. As of December 31, 2025 and December 31, 2024, we had foreign currency denominated accounts payable and accrued expenses of $129.0 million and $72.4 million, respectively. As of December 31, 2025 and December 31, 2024, we had foreign currency denominated property, plant and equipment of $223.7 million and $157.6 million, respectively. As of December 31, 2025 and December 31, 2024, we had foreign currency denominated other assets of $148.1 million and $62.5 million, respectively. To date, foreign currency transaction gains and losses have not been material to our consolidated financial statements. The following table shows the impact of a hypothetical 10% increase or decrease in current exchange rates on our net assets as of December 31, 2025 and our net loss for the 12 months ended December 31, 2025:

(in thousands)

Hypothetical Change in Currency Exchange Rates

As our foreign currency risk increases in the future, we will evaluate alternative strategies, including hedging, to mitigate our foreign currency exposure.

Effects of Inflation

The rate of inflation in the United States has risen to levels not experienced in decades. Inflation generally affects us by increasing our cost of labor and research and development contract costs. The extent of any future impacts from inflation on our business and our results of operations will be dependent upon how long the elevated inflation levels persist and if the rate of inflation were to accelerate, neither of which we are able to predict. If elevated levels of inflation were to persist

121

Table of Contents

or if the rate of inflation were to further increase, the purchasing power of our cash and cash equivalents may be eroded, our expenses could increase faster than anticipated and we may utilize our capital resources sooner than expected. We do not believe inflation had a material effect on our consolidated results of operations during the periods presented.

122

Table of Contents

Item 8. Consolidated Financial Statements and Supplementary Data.

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Report of Independent Registered Public Accounting Firm – PCAOB ID No. 34 124

Consolidated Balance Sheets 126

Consolidated Statements of Operations 127

Consolidated Statements of Comprehensive Loss 127

Consolidated Statements of Stockholders’ Equity 129

Consolidated Statements of Cash Flows 130

Notes to Consolidated Financial Statements 130

123

Table of Contents

Report of Independent Registered Public Accounting Firm

To the stockholders and the Board of Directors of Vaxcyte, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Vaxcyte, Inc. and subsidiary (the "Company") as of December 31, 2025 and 2024, the related consolidated statements of operations, comprehensive loss, stockholders' equity, and cash flows, for each of the three years in the period ended December 31, 2025, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 24, 2026, expressed an unqualified opinion on the Company's internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Accrued Contract Manufacturing Expenses — Refer to Notes 2 and 7 to the financial statements

Critical Audit Matter Description

The Company incurs research and development expenses, including those performed by Lonza, a contract manufacturing organization, under development and manufacturing services agreements, to provide research and development services related to preclinical and clinical-stage vaccine development. At the end of each period, the Company accrues for costs related to manufacturing expenses based on their estimates of the services received for each phase and efforts expended pursuant to quotes and contracts with vendors that conduct research and development on their behalf. This estimation process involves reviewing open contracts and purchase orders, communicating with Company personnel and third parties to identify services that have been performed on their behalf, and estimating the level of service performed and the associated costs incurred for the services for each phase when the Company has not yet been invoiced or otherwise notified of the actual costs.

We identified the Company’s accrued contract manufacturing expenses as a critical audit matter primarily due to judgments necessary for management to estimate the cost of services provided but not yet invoiced and the significant volume of

124

Table of Contents

transactions. The amount of the accrual at period end is based on the terms and conditions per the agreements and is dependent on management’s gathering of information from various sources, including Lonza, regarding the progress of the uninvoiced services at the reporting date. Accordingly, this estimate is subjective as it involves management’s judgment to analyze the various sources of information. This required extensive audit effort due to the volume and nature of available information from various sources, including Lonza, and required a high degree of auditor judgment when performing audit procedures to audit management’s estimates of accrued contract manufacturing expenses and evaluating the results of those procedures.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to the accrued contract manufacturing expenses included the following, among others:

•We tested the effectiveness of controls over the Company’s accrued contract manufacturing expense process, including controls over the estimation of contract manufacturing activities completed to date.

•We met with internal research and development personnel and inspected Board of Directors materials to understand the status of contract manufacturing activities. We then compared this information to the judgment applied in management’s estimate of the recorded expenses and corresponding accrual.

•We evaluated the completeness of accrued contract manufacturing expenses through subsequent disbursement testing, and by tracing selected contract stages from the tracker obtained from Lonza, the Company’s most significant contract manufacturer, to the contract stages used by the Company.

•For a sample of contract stages, we evaluated the accrued contract manufacturing expenses by:

◦Sending written confirmations directly to the contract manufacturing organization to confirm the total budgeted amount and percentage of completion incurred as of year-end.

◦Inspecting the development and manufacturing services agreement and related amendments, change orders, statements of work, and agreeing key provisions of the agreements including timeline, budget, and relevant rates, to the Company’s analysis of estimated expenses incurred to date.

◦Obtaining invoices, if available, to substantiate when the transaction should have been recorded.

◦Obtaining cash disbursements to test the accuracy of the accrual.

◦Performing a lookback analysis by comparing the estimated accrual balance as of December 31, 2024, to the invoices received after year-end to evaluate the Company’s ability to estimate the accrual.

/s/ Deloitte & Touche LLP

San Francisco, California

February 24, 2026

We have served as the Company’s auditor since 2017.

125

Table of Contents

VAXCYTE, INC.

Consolidated Balance Sheets

(in thousands, except share and per share data)

December 31,

Assets

Current assets:

Prepaid expenses and other current assets 66,402 40,777

Liabilities and Stockholders' Equity

Current liabilities:

Accrued contract manufacturing expenses 74,654 36,159

Operating lease liabilities — current 6,124 5,891

Commitments and contingencies (Note 7)

Stockholders' Equity

Accumulated other comprehensive income (loss) 1,587 (3,873)

The accompanying notes are an integral part of these consolidated financial statements.

126

Table of Contents

VAXCYTE, INC.

Consolidated Statements of Operations

(in thousands, except share and per share data)

Year Ended December 31,

Operating expenses:

Acquired manufacturing rights (Note 7) — — 75,000

Other income, net:

Net loss per share, basic and diluted $ (5.63) $ (3.80) $ (4.14)

The accompanying notes are an integral part of these consolidated financial statements.

127

Table of Contents

VAXCYTE, INC.

Consolidated Statements of Comprehensive Loss

(in thousands)

Year Ended December 31,

Other comprehensive loss:

Unrealized gains (losses) on investments 9,463 (4,398) 538

Foreign currency translation adjustments, net (4,003) 346 2

The accompanying notes are an integral part of these consolidated financial statements.

128

Table of Contents

VAXCYTE, INC.

Consolidated Statements of Stockholders’ Equity

(in thousands, except share data)

Shares Amount

Stock-based compensation expense — — 48,760 — — 48,760

Other comprehensive income — — — — 540 540

Stock-based compensation expense — — 84,822 — — — 84,822

Other comprehensive loss — — — — — (4,052) (4,052)

Other comprehensive income — — — — 5,460 5,460

The accompanying notes are an integral part of these consolidated financial statements.

129

Table of Contents

VAXCYTE, INC.

Consolidated Statements of Cash Flows

(in thousands)

Year Ended December 31,

Cash flows from operating activities:

Adjustments to reconcile net loss to net cash used in operating activities:

Amortization of operating lease right-of-use assets 8,464 8,842 7,015

Unrealized foreign exchange loss (gain) (34,768) 4,232 —

Changes in operating assets and liabilities:

Cash flows from investing activities:

Cash flows from financing activities:

Effect of exchange rate changes on cash and cash equivalents 2,439 426 (6,686)

Reconciliation of cash, cash equivalents and restricted cash:

Supplemental disclosures of non-cash investing and financing activities:

The accompanying notes are an integral part of these consolidated financial statements.

130

Table of Contents

VAXCYTE, INC.

Notes to Consolidated Financial Statements

1. Company Organization and Nature of Business

Vaxcyte, Inc. (“we,” “our,” “us,” “Vaxcyte” and the “Company”) refers to Vaxcyte, Inc., a Delaware corporation, and our wholly-owned consolidated subsidiary, or as the context may require, Vaxcyte, Inc. only. We are headquartered in San Carlos, California, and were incorporated in the state of Delaware on November 27, 2013 as SutroVax, Inc., and changed our name to Vaxcyte, Inc. on May 15, 2020. We are a clinical-stage vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases. We are re-engineering the way highly complex vaccines are made through the XpressCFTM cell-free protein synthesis platform. Unlike conventional cell-based approaches, our system for producing difficult-to-make proteins and antigens is intended to develop and deliver high-fidelity vaccines with enhanced immunological benefits that are beyond the capabilities of conventional approaches.

Our primary activities since incorporation have been to perform research and development, undertake preclinical and clinical studies and conduct manufacturing activities in support of our product development and commercial readiness efforts; organize and staff our Company; establish our intellectual property portfolio; and raise capital to support and expand such activities.

2. Basis of Presentation and Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and applicable rules and regulations of the Securities and Exchange Commission (the “SEC”) regarding annual reporting.

The consolidated financial statements include the Company and its wholly owned subsidiary. All intercompany transactions and balances have been eliminated upon consolidation.

Certain prior period amounts in the consolidated financial statements have been reclassified to conform to current period presentation.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities and expenses and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements. On an ongoing basis, we evaluate our estimates and assumptions, including those related to stock-based compensation expense, accruals for certain research and development costs, the valuation of deferred tax assets and income taxes. Management bases our estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ materially from those estimates.

Concentration of Credit Risk and Other Risks and Uncertainties

Financial instruments that potentially subject us to a concentration of credit risk consist primarily of cash, cash equivalents and investments. We invest in money market funds, U.S. Treasury securities, U.S. government agency securities, corporate debt, commercial paper and asset-backed securities. We maintain bank deposits in federally insured financial institutions and these deposits may exceed federally insured limits. We are exposed to credit risk in the event of a default by the financial institutions holding our cash and issuers of investments to the extent recorded on the consolidated balance sheets. Our investment policy limits investments to money market funds, certain types of debt securities issued by the U.S. Government and its agencies, corporate debt, commercial paper and asset-backed securities, and places restrictions on the credit ratings, maturities and concentration by type and issuer. We have not experienced any significant losses on our deposits of cash, cash equivalents or investments.

We are subject to supplier concentration risk from certain vendors. Although we are working to establish secondary sources of supply, we currently source several of our critical raw materials from single-source suppliers. We currently use a contract manufacturing organization (“CMO”), Lonza Ltd. (“Lonza”), to handle most of our manufacturing activities for our VAX-31 and VAX-24 programs. As another CMO, Patheon Manufacturing Services LLC, part of Thermo Fisher

131

Table of Contents

Scientific (collectively, “Thermo Fisher”) will formulate, fill, inspect, package, label, test, manufacture and supply drug product for our PCV programs. If we were to experience disruptions in raw materials supplied by our suppliers, or in manufacturing activities at Lonza and/or at Thermo Fisher, we may experience significant delays in our product development timelines and may incur substantial costs to secure alternative sources of raw materials or manufacturing.

The “Risk Factors” section of this Annual Report on Form 10-K describes more details on these risks and other risks and uncertainties that could affect our business and our future.

Cash, Cash Equivalents and Restricted Cash

We consider all highly liquid investments purchased with original maturities of three months or less from the date of purchase to be cash equivalents. Cash equivalents consist primarily of amounts invested in money market funds and commercial paper and are stated at their fair values. Restricted cash consists of three standby letters of credit that serve as collateral for the lease agreements for our current corporate headquarters.

Investments

Our investments have been classified and accounted for as available-for-sale securities. Fixed income securities consist of U.S. Treasury securities, U.S. government agency securities, corporate debt, commercial paper and asset-backed securities. These securities are recorded on the consolidated balance sheets at fair value. Unrealized gains and losses on these securities are included as a separate component of accumulated other comprehensive gain (loss). The cost of investment securities is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion are included in other income (expense), net. Realized gains and losses are also included in other income (expense), net. When the fair value of a debt security declines below its amortized cost basis, any portion of that decline attributable to credit losses, to the extent expected to be nonrecoverable before the sale of the security, is recognized in our consolidated statements of operations. When the fair value of a debt security declines below its amortized cost basis due to changes in interest rates, such amounts are recorded in other comprehensive loss, and are recognized in our consolidated statements of operations only if we sell or intend to sell the security before recovery of its cost basis.

Fair Value Measurements

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. The carrying amounts of our financial instruments, including cash and cash equivalents, prepaid and other current assets, accounts payable, accrued expenses, and other liabilities, approximate fair value due to their short-term maturities.

Assets and liabilities recorded at fair value on a recurring basis in the consolidated balance sheets, as well as assets and liabilities measured at fair value on a non-recurring basis or disclosed at fair value, are categorized based upon the level of judgment associated with inputs used to measure their fair values. The accounting guidance for fair value provides a framework for measuring fair value and requires certain disclosures about how fair value is determined. Fair value is defined as the price that would be receivedupon the sale of an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance also establishes a three-level valuation hierarchy that prioritizes the inputs to valuation techniques used to measure fair value based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows:

Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level 3—Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.

Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability.

132

Table of Contents

Changes in the ability to observe valuation inputs may result in a reclassification of levels of certain securities within the fair value hierarchy. We recognize transfers into and out of levels within the fair value hierarchy in the period in which the actual event or change in circumstances that caused the transfer occurs.

Level 1 securities consist of highly liquid money market funds for which the carrying amounts approximate their fair values due to their short maturities. U.S. Treasury securities are valued using Level 1 inputs based on unadjusted, quoted prices in active markets that are observable at the measurement date for identical assets or liabilities. Level 2 securities, consisting of corporate debt, commercial paper, U.S. government agency securities and asset-backed securities, are measured based on other observable inputs, including broker or dealer quotations or alternative pricing sources. When quoted prices in active markets for identical assets or liabilities are not available, we rely on non-binding quotes from our investment managers, which are based on proprietary valuation models of independent pricing services. These models generally use inputs such as observable market data, quoted market prices for similar instruments or historical pricing trends of securities relative to our peers. To validate the fair value determinations provided by our investment managers, we review the pricing movement in the context of overall market trends and trading information from our investment managers. In addition, we assess the inputs and methods used in determining the fair value in order to determine the classification of securities in the fair value hierarchy.

Property and Equipment, Net

Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally three to five years. Leasehold improvements are amortized over the shorter of the expected life or lease term. Repairs and maintenance expenditures, which are not considered improvements and do not extend the useful life of property and equipment, are expensed as incurred. When assets are retired or otherwise disposed of, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheets and the resulting gain or loss is reflected in the consolidated statements of operations in the period realized.

Leases

We determine if an arrangement is a lease at inception. In addition, we determine whether a lease meets the classification criteria of a finance or operating lease at the lease commencement date considering whether: (i) the lease transfers ownership of the underlying asset to the lessee at the end of the lease term; (ii) the lease grants the lessee an option to purchase the underlying asset that the lessee is reasonably certain to exercise; (iii) the lease term is for a major part of the remaining economic life of the underlying asset; (iv) the present value of the sum of the lease payments and residual value guaranteed by the lessee equals or exceeds substantially all of the fair value of the underlying asset; and (v) the underlying asset is such a specialized nature that it is expected to have no alternative use to the lessor at the end of the lease term. As of December 31, 2025 and 2024, our lease population consisted of real estate operating leases and we did not have any finance leases.

Operating leases are included in Operating lease right-of-use (“ROU”) assets, Operating lease liabilities — current and Operating lease liabilities — long term in our consolidated balance sheets. ROU assets represent our right to use the underlying assets for the lease term and lease liabilities represent our obligation to make lease payments arising from the leases. Operating lease ROU assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the present value of lease payments, if the rate implicit in the lease is not readily determinable, we use our incremental borrowing rate based on the information available at the lease commencement date. We determine the incremental borrowing rate based on an analysis of corporate bond yields with a credit rating similar to ours. The determination of our incremental borrowing rate requires management judgment, including development of a synthetic credit rating and cost of debt, as we currently do not carry any debt. We believe that the estimates used in determining the incremental borrowing rate are reasonable based upon current facts and circumstances. Applying different judgment to the same facts and circumstances could yield a different incremental borrowing rate. The operating lease ROU assets also include adjustments for prepayments and accrued lease payments and exclude lease incentives. ROU assets and lease liabilities may include options to extend or terminate leases if it is reasonably certain that we will exercise such options. Lease payments which are fixed and determinable are amortized as rent expense on a straight-line basis over the expected lease term. Variable lease costs, which are dependent on usage, a rate or index, including common area maintenance charges, are expensed as incurred. Lease agreements that include lease and non-lease components are accounted for as a single lease component. Lease agreements with non-cancelable terms of less than 12 months are not recorded on our consolidated balance sheets.

133

Table of Contents

Impairment of Long-Lived Assets

We review long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Recoverability is measured by comparing the carrying amount to the future undiscounted net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured as the amount by which the carrying amount of the assets exceeds the projected discounted future net cash flows generated by the assets. There were no impairments of long-lived assets during the years ended December 31, 2025, 2024 or 2023.

Research and Development

Research and development costs are expensed as incurred. Research and development costs include salaries, stock-based compensation and benefits for employees performing research and development activities, an allocation of facility and overhead expenses, expenses incurred under agreements with consultants, CMOs, contract research organizations (“CROs”) and investigative sites that conduct preclinical studies, clinical trials other supplies and costs associated with product development efforts, preclinical activities, clinical trials and regulatory operations.

Acquired Manufacturing Rights

Acquired manufacturing rights are expensed as incurred on our consolidated statements of operations when it is determined there is no alternative future use.

Total research and development costs including acquired manufacturing rights were $794.3 million, $476.6 million and $407.3 million for the years ended December 31, 2025, 2024 and 2023, respectively.

Accrued Research and Development

We have entered into various agreements with CROs and CMOs. Our research and development accruals, which include accrued manufacturing expenses, are estimated based on the level of services performed, progress of the studies, including the phase or completion of events, and contracted costs. The estimated costs of research and development services provided, but not yet invoiced, are included in accrued expenses on the consolidated balance sheets. If the actual timing of the performance of services or the level of effort varies from the original estimates, we adjust the accrual accordingly. Payments made to CROs or CMOs under these arrangements in advance of the performance of the related services are recorded as prepaid expenses and other current assets until the services are rendered. To date, there have been no material differences between our estimates of such expenses and the amounts actually incurred.

Income Taxes

We account for income taxes using the asset and liability method. We recognize deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements or tax returns. Deferred tax assets and liabilities are determined based on the difference between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse.

In evaluating the ability to recover our deferred income tax assets, we consider all available positive and negative evidence, including our operating results, ongoing tax planning and forecasts of future taxable income on a jurisdiction-by-jurisdiction basis. In the event we determine that we would be able to realize our deferred income tax assets in the future in excess of their net recorded amount, we would make an adjustment to the valuation allowance that would reduce the provision for income taxes. Conversely, in the event that all or part of the net deferred tax assets are determined not to be realizable in the future, an adjustment to the valuation allowance would be charged to earnings in the period when such determination is made. As of December 31, 2025 and 2024, we have recorded a full valuation allowance on our deferred tax assets.

Tax benefits related to uncertain tax positions are recognized when it is more likely than not that a tax position will be sustained during an audit. Interest and penalties related to unrecognized tax benefits are included within the provision for income tax.

134

Table of Contents

Stock-Based Compensation Expense

For equity awards granted to employees, non-employees and directors, stock-based compensation is measured at grant date based on the fair value of the award. We determine the grant-date fair value of stock options with only service conditions using the Black-Scholes option-pricing model. The fair value of restricted stock and restricted stock unit (“RSU”) awards with only service conditions are determined based on the number of units granted and the closing price of our common stock as of the grant-date. The grant-date fair value of awards with only service conditions is recognized as share-based compensation expense on a straight-line basis over the employees’ requisite service period or the non-employees’ vesting period as the services are rendered.

The estimated fair value of awards that contain market conditions are determined based on the Monte Carlo simulation model. We recognize share-based compensation expense for awards with market conditions on a straight-line basis over the requisite service period for each separately vesting portion of the award. Forfeitures are accounted for as they occur.

Comprehensive Loss

Comprehensive loss includes net loss and other comprehensive loss for the period. Other comprehensive loss consists of unrealized loss on investments and foreign currency translation adjustments, net.

Foreign Currency Transactions

For our international operations, the local currency has been determined to be the functional currency. We translate functional currency assets and liabilities to their U.S. dollar equivalents at exchange rates in effect as of the balance sheet date and income and expense amounts at average exchange rates for the period. Gains and losses from foreign currency translation are included in accumulated other comprehensive loss within stockholders’ equity in the consolidated balance sheets.

Net Loss Per Share

Basic net loss per common share is calculated by dividing the net loss by the weighted-average number of common stock outstanding, including pre-funded warrants, during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, common stock subject to repurchase, and stock options are considered to be potentially dilutive securities. Shares of common stock into which the pre-funded warrants may be exercised are considered outstanding for the purposes of computing net loss per share because the shares may be issued for little consideration, are fully vested and are exercisable after the original issuance date.

Recently Adopted Accounting Standards

In December 2023, the FASB issued Accounting Standards Update ("ASU") 2023-09—Income Taxes: Improvements to Income Tax Disclosures, which includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The new standard is effective for annual periods beginning after December 15, 2024. We adopted this ASU on a retrospective basis effective with our annual reporting period beginning January 1, 2025. See Note 12, Income Taxes for additional information.

Recently Issued Accounting Standards Not Yet Adopted

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies and adopted by us as of the specified effective date. We believe that the impact of recently issued standards that are not yet effective will not have a material impact on our consolidated financial statements and disclosures.

In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40) (“ASU 2024-03”). The amendments in ASU 2024-03 intend to improve the disclosures about a public business entity’s expenses and address requests from investors for more detailed information about the types of expenses (including purchases of inventory, employee compensation, depreciation, amortization and depletion). This new guidance is effective for us for annual periods beginning after December 15, 2026. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

135

Table of Contents

In September 2025, the FASB issued ASU No. 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software (“ASU 2025-06”). The amendments in ASU 2025-06 intend to modernize the accounting for software costs that are accounted for under Subtopic 350-40, Intangibles—Goodwill and Other—Internal-Use Software (referred to as “internal-use software”). This new guidance is effective for us for annual periods beginning after December 15, 2027. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832): Accounting for Government Grants Received by Business Entities. The amendments in ASU 2025-10 intend to establish authoritative guidance on the accounting for government grants received by business entities. This guidance is effective for us beginning with our 2029 fiscal year annual reporting period, with early adoption permitted. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-11 to amend the guidance in “Interim Reporting” (Topic 270). The update provides clarifications intended to improve the consistency and usability of interim disclosure requirements, including a comprehensive listing of required interim disclosures and a new disclosure principle for reporting material events occurring after the most recent annual period. The amendments do not change the underlying objectives of interim reporting but are designed to enhance clarity in application. The guidance is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

In December 2025, the FASB issued ASU 2025-12 “Codification Improvements” to address suggestions received from stakeholders on the Accounting Standards Codification ("the Codification") and to make other incremental improvements to U.S. GAAP. The update represents changes to the Codification that (i) clarify, (ii) correct errors, or (iii) make minor improvements. The amendments make the Codification easier to understand and apply. The guidance is effective for fiscal years beginning after December 15, 2026, including interim periods within those fiscal years. We are currently evaluating the impact of this guidance on our consolidated financial statements and related disclosures.

3. Fair Value Measurements and Fair Value of Financial Instruments

The following tables set forth our financial instruments measured at fair value on a recurring basis by level within the fair value hierarchy at December 31, 2025 and 2024:

Assets (in thousands)

Cash and cash equivalents:

U.S. Treasury securities Level 1 — — — —

Investments:

136

Table of Contents

Assets (in thousands)

Cash and cash equivalents:

Investments:

We had no Level 3 securities either as of December 31, 2025 or 2024.

There were no transfers within the hierarchies during the years ended December 31, 2025 or 2024.

As of December 31, 2025 and 2024, we had investments with a total fair market value of $0.3 billion and $1.5 billion in an unrealized loss position, of which $120.2 million and $10.5 million, respectively, were in a continuous unrealized loss position for more than 12 months. The gross unrealized losses of securities that have been in a continuous unrealized loss position were not material at December 31, 2025 or $7.2 million at December 31, 2024.

Unrealized losses related to our investments are primarily due to interest rate fluctuations as opposed to credit quality. We do not intend to sell any of the securities in an unrealized loss position and it is not likely that we would be required to sell these securities before recovery of their amortized cost basis, which may be at maturity. We did not recognize any credit losses related to our investments during the years ended December 31, 2025 or 2024.

The following table presents the contractual maturities of our investments as of December 31, 2025 (in thousands):

Fair Value

Due in less than one year $ 1,387,000

Due in one to five years 881,664

4. Commercial Manufacturing and Supply Agreements

Lonza Ltd. ("Lonza")

On October 13, 2023, we entered into a pre-commercial services and commercial manufacturing supply agreement with Lonza (the “ Lonza Commercial Manufacturing and Supply Agreement”).

Pursuant to the Lonza Commercial Manufacturing and Supply Agreement, Lonza will (i) construct and build out a dedicated suite (the “Suite”) at Lonza’s facilities in Visp, Switzerland to manufacture certain key components (including drug substance) for our proprietary PCV franchise and any other products or intermediates we may choose (collectively, the “Products”) and (ii) maintain and operate the Suite (utilizing Lonza’s employees) to manufacture the Products as a

137

Table of Contents

service provided to us, including conducting related quality control and quality assurance operations. Lonza will be a preferred, non-exclusive, supplier of the Products to us, and we retain the right to procure the Products from one or more alternate and/or backup manufacturers of the Products (including at our own facilities).

Unless earlier terminated, the Lonza Commercial Manufacturing and Supply Agreement will remain in effect until December 31, 2038, subject to automatic renewal for up to three additional renewal periods of five years each, unless we elect not to renew (with 24 months advanced notice to Lonza). We are permitted to terminate the Commercial Manufacturing and Supply Agreement for convenience or for Lonza’s uncured material breach, in each case subject to certain notice obligations. Lonza is permitted to terminate the Lonza Commercial Manufacturing and Supply Agreement in the event that we commit certain specified material breaches, including uncured failure to pay material and undisputed amounts of money due to Lonza, subject to certain notice obligations. Either party may terminate the Commercial Manufacturing and Supply Agreement in certain circumstances in the event of the other party’s bankruptcy. In the event that we terminate the agreement for convenience, or Lonza terminates the agreement in the event that we commit certain specified material breaches, then certain termination consequences may be triggered, including that (i) we would forfeit any outstanding entitlement to credit from Lonza of the Repurposing Fee (as defined below), and (ii) we would be obligated to pay Lonza a termination penalty equal to the greater of (a) CHF 70.0 million, or (b) a prespecified number of months’ FTE fees for the actual FTEs assigned to us as of the date of termination. Within 30 days of the Effective Date, we paid Lonza a repurposing fee (the “Repurposing Fee”) of CHF 27.0 million that will be credited back to us over a 10-year period starting upon commencement of commercial production. In the event of a termination under certain circumstances, Lonza shall be obligated to provide certain wind-down and transition services to us for up to 12 months and 24 months, respectively.

As of December 31, 2025 and 2024, we have incurred $217.1 million and $151.8 million of capital expenditures related to the Vaxcyte owned facility buildout and equipment, respectively. In addition, as of December 31, 2025 and 2024, we have incurred $118.3 million and $62.5 million of facility buildout expenditures that are owned and controlled by Lonza, including the Repurposing Fee, which have been accounted for as prepaid lease payments and will be recorded as a ROU asset under Accounting Standards Codification ("ASC") 842 when control over the Suite is transferred to us, which we expect to occur when the buildout of the Suite is complete and manufacturing activities commence (see Note 5, “Balance Sheet Details”), respectively.

Thermo Fisher Scientific

On September 24, 2025, we entered into a master services agreement with Patheon Manufacturing Services LLC, part of Thermo Fisher Scientific (collectively, “Thermo Fisher”), pursuant to which Thermo Fisher will formulate, fill, inspect, package, label, test, manufacture and supply drug product for us at its facility in Greenville, North Carolina (the "Thermo Fisher Commercial Manufacturing and Supply Agreement"). Pursuant to the Thermo Fisher Commercial Manufacturing and Supply Agreement, we have agreed to order drug product from Thermo Fisher based on certain binding forecast periods and established prices. In addition, we will also pay Thermo Fisher for technology transfer activities and reimburse Thermo Fisher for certain out-of-pocket capital expenditures under the terms of the agreement.

138

Table of Contents

5. Balance Sheet Details

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets as of December 31, 2025 and 2024 consisted of the following:

December 31,

(in thousands)

Deposits for equipment purchases 1,208 327

Property and Equipment, Net

Property and equipment, net as of December 31, 2025 and 2024 consisted of the following:

December 31,

(in thousands)

Computers, computer software and office equipment 1,670 1,001

Less: accumulated depreciation and amortization (32,770) (16,274)

Depreciation and amortization expense for the years ended December 31, 2025, 2024, and 2023 was $16.4 million, $7.0 million, and $3.2 million, respectively.

Other Assets

Other assets as of December 31, 2025 and 2024 consisted of the following:

December 31,

(in thousands)

Manufacturing facility construction buildout $ 118,339 $ 62,477

139

Table of Contents

Accrued Expenses

Accrued expenses as of December 31, 2025 and 2024 consisted of the following:

December 31,

(in thousands)

6. Leases

Operating Lease Obligations

Office facility

In January 2021, we entered into a lease agreement (the “Original Lease”) for our current corporate headquarters facility located in San Carlos, California (the “Headquarters Facility”). The lease term began on December 3, 2021, as amended on October 17, 2023, and was set to expire on December 31, 2025.

In September 2023, we entered into an assignment and assumption of lease agreement (the “Assignment Agreement”) for an expanded lease space in the same building as our Headquarters Facility (the “Assumed Lease Premises”). The assumed lease had an original contractual term of 10 years, set to expire on November 30, 2031. Pursuant to the Assignment Agreement, the base rent was abated for three full calendar months following the October 1, 2023 effective date of the Assignment Agreement. Thereafter, we were obligated to pay an aggregate of approximately $1.9 million in rent payments for the remaining nine months of the first year, with a 3% rent adjustment (not inclusive of rent abatement) every year thereafter.

PCVX US Equity

PCVX · 10-K · period ended 2025-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Item 8. Consolidated Financial Statements and Supplementary Data.

PCVX US Equity☆

PCVX · 10-K · period ended 2025-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Item 8. Consolidated Financial Statements and Supplementary Data.

PCVX US Equity