A Study to Learn About the Safety, Tolerability, and Immunogenicity of a Fifth Dose of 6-Valent OspA-Based Lyme Disease Vaccine

NCT07500506 · tracked via the Priya Life Science USA tracker

Sponsor

Pfizer

Phase

Phase 3

Started

2026-04-08

Last updated

2026-05-06

Condition(s) studied

Lyme Disease

Investigational drug(s) / intervention(s)

VLA15Placebo

VLA15: VLA15 injection IM

Placebo: Saline Injection

Study summary

The purpose of this study is to learn about the safety effects of the Lyme disease vaccine (called VLA15), and its ability to protect people from Lyme disease after a 5th dose of the vaccine.

This study is seeking participants who:

* are generally healthy and 7 years of age and older,
* have already been vaccinated with 4 doses of VLA15 (from the VALOR study), and have blood sample taken post dose 4.
* are not currently taking, or haven't recently taken, medicines like chemotherapy, blood products, or blood thinners.
* are not pregnant or breastfeeding and do not plan to become pregnant while receiving the study vaccine.

All participants in this study will receive a total of 1 dose through a shot in the upper arm, either VLA15 or saline shot (saltwater).

The study will compare the experiences of people receiving the study vaccine or saltwater shot.

Participants will take part in this study for about 12 months. During this time, they will have 4 planned clinic visits. The clinic visits may include having a health check, giving a small amount of blood and getting the study vaccine or saltwater as a shot at the first visit.

Eligibility

Sex

ALL

Min age

7 Years

Max age

—

Healthy volunteers

Accepted

Inclusion Criteria: * Participants who are healthy as determined by medical history and clinical judgment. * Participants willing and able to comply with all scheduled visits, IP receipt, and other procedures throughout the study. * Able to provide Informed Consent. * Participants must have received 4 doses of VLA15 in the C4601003 study, and have a V7 blood sample available. Exclusion Criteria: * Pregnant or breastfeeding participants. * Allergies or contraindications to vaccines or their components. * Health issues including: blood clotting deficiencies, immunodeficiencies, bone marrow disorder, or uncontrolled psychiatric conditions. * Receipt of therapies to treat malignancies, blood/plasma products and immunoglobulins, systemic corticosteroids and immunosuppressants, or anticoagulant therapy in recent medical history. * Recent or concurrent participation in a separate interventional study. * Staff or direct family of the study site staff and Sponsor.

Primary outcome measure(s)

Percentage of participants reporting prespecified local reactions — Within 7 days following each study intervention administration
Percentage of participants reporting prespecified systemic events — Within 7 days following each study intervention administration
Percentage of participants reporting adverse events (AEs) — Through 1 month following study intervention administration
Percentage of participants reporting newly diagnosed chronic medical conditions (NDCMCs) — Through study completion, up to approximately 12 months.
Percentage of participants reporting serious adverse events (SAEs) — Through study completion, up to approximately 12 months.
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6) — At 1 month after completion of Dose 5
Objective to determine non-inferiority of Dose 5 compared to Dose 4 in all participants when there is a 1 year gap between Dose 4 and Dose 5.
Sero-response of anti-OspA IgG concentrations for each serotype (ST1-ST6). — At 1 month after completion of Dose 5
Difference in seroresponse rate between 1 month after Dose 5 and 1 month after Dose 4 for each serotype in all participants ≥7 years of age who received a fifth dose of VLA15 1 year after their fourth dose of VLA15.

Trial sites (22)

Facility	City	Region	Status
Northern Light Eastern Maine Medical Center	Bangor	Maine	Not Yet Recruiting
Northern Light Family Medicine and Residency Center	Bangor	Maine	Not Yet Recruiting
University of Massachusetts Chan Medical School	Worcester	Massachusetts	Recruiting
Hunterdon Medical Center	Flemington	New Jersey	Not Yet Recruiting
Smith Allergy and Asthma Specialists	Cortland	New York	Recruiting
Smith Allergy & Asthma Specialists	Horseheads	New York	Recruiting
Altoona Center For Clinical Research	Duncansville	Pennsylvania	Recruiting
Allegheny Health and Wellness Pavilion	Erie	Pennsylvania	Recruiting
Central Erie Primary Care	Erie	Pennsylvania	Recruiting
Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18)	Pittsburgh	Pennsylvania	Recruiting
Preferred Primary Care Physicians, Preferred Clinical Research - St.Clair	Pittsburgh	Pennsylvania	Not Yet Recruiting
Robert Packer Hospital	Sayre	Pennsylvania	Recruiting
Frontier Clinical Research, LLC	Scottdale	Pennsylvania	Recruiting
Northeast Clinical Trials Group	Scranton	Pennsylvania	Recruiting
Frontier Clinical Research, LLC	Smithfield	Pennsylvania	Recruiting
Preferred Primary Care Physicians	Uniontown	Pennsylvania	Not Yet Recruiting
Velocity Clinical Research, Providence	East Greenwich	Rhode Island	Not Yet Recruiting
The University of Vermont Medical Center Inc.	Burlington	Vermont	Not Yet Recruiting
Amherst Family Practice, P.C.	Winchester	Virginia	Not Yet Recruiting
Milestone Research Inc.	London	Ontario	Not Yet Recruiting
Stouffville Medical Research Institute Inc.	Stouffville	Ontario	Not Yet Recruiting
Diex Recherche Inc. Division Sherbrooke	Sherbrooke	Quebec	Recruiting

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Official registry record

This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.

View NCT07500506 on ClinicalTrials.gov ↗ ← All trials in the USA