A Study to Learn About the Safety, Tolerability, and Immunogenicity of a Fifth Dose of 6-Valent OspA-Based Lyme Disease Vaccine
← catalyst calendarNCT07500506 · readout in 107 d
Sponsored by Pfizer (industry) · PFE — their whole pipeline →.
Phase
Phase 3
Status
Recruiting
Study type
Interventional
Design
Randomized · Triple · Prevention
Enrollment
1,712estimated
Sites
22
Countries
Canada, United States
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2026-04-08 | actual | When the study began enrolling |
| Primary completion | 2026-12-04 | estimated | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2026-12-04 | estimated | The whole study's end, after follow-up |
| First posted | 2026-03-30 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-05-06 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Condition
- Lyme Disease
Interventions
- Biological: VLA15
- Biological: Placebo
Primary outcomes
what the primary-completion date above is the date OFPercentage of participants reporting prespecified local reactions
measured Within 7 days following each study intervention administration
Percentage of participants reporting prespecified systemic events
measured Within 7 days following each study intervention administration
Percentage of participants reporting adverse events (AEs)
measured Through 1 month following study intervention administration
Percentage of participants reporting newly diagnosed chronic medical conditions (NDCMCs)
measured Through study completion, up to approximately 12 months.
Percentage of participants reporting serious adverse events (SAEs)
measured Through study completion, up to approximately 12 months.
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
measured At 1 month after completion of Dose 5
Sero-response of anti-OspA IgG concentrations for each serotype (ST1-ST6).
measured At 1 month after completion of Dose 5
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