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

Last updated: May 4, 2026
Sponsor: Pfizer
Overall Status: Active - Recruiting

Phase

3

Condition

Lyme Disease

Rash

Treatment

VLA15

Placebo

Clinical Study ID

NCT07500506
C4601016
  • Ages > 7
  • All Genders
  • Accepts Healthy Volunteers

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 Criteria

Inclusion

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, andother procedures throughout the study.

  • Able to provide Informed Consent.

  • Participants must have received 4 doses of VLA15 in the C4601003 study, and have aV7 blood sample available.

Exclusion

Exclusion Criteria:

  • Pregnant or breastfeeding participants.

  • Allergies or contraindications to vaccines or their components.

  • Health issues including: blood clotting deficiencies, immunodeficiencies, bonemarrow disorder, or uncontrolled psychiatric conditions.

  • Receipt of therapies to treat malignancies, blood/plasma products andimmunoglobulins, systemic corticosteroids and immunosuppressants, or anticoagulanttherapy in recent medical history.

  • Recent or concurrent participation in a separate interventional study.

  • Staff or direct family of the study site staff and Sponsor.

Study Design

Total Participants: 1712
Treatment Group(s): 2
Primary Treatment: VLA15
Phase: 3
Study Start date:
April 08, 2026
Estimated Completion Date:
December 04, 2026

Study Description

A Phase 3, Randomized, Placebo-Controlled, Double-Blinded Study to Evaluate the Safety, Tolerability, and Immunogenicity of a Fifth Dose of 6-Valent OspA-Based Lyme Disease Vaccine, VLA15, in Healthy Participants ≥7 Years of Age

Participants will be randomized in a 5:1 ratio to receive either one dose of VLA15 or placebo (saline) at the first visit. This study will use an external data monitoring committee (EDMC). The EDMC is independent of the Pfizer study team and includes only external members. The EDMC charter describes the role of the EDMC in more detail.

Approximately 1712 participants will be enrolled in the study.

Healthy individuals 7 years of age and older who have received 4 prior doses of active VLA15 from the C4601003 study, have a blood sample taken post dose 4, are willing to comply with all study procedures, and provide signed informed consent will be enrolled. Pregnant or breastfeeding individuals and fertile individuals who are unwilling or unable to use effective contraceptive methods as outlined in this protocol will not be enrolled. Individuals who have contraindication to vaccination, conditions or treatments that can inhibit the ability to mount an immune response to a vaccine, or other conditions that may increase the risk of study participation will be excluded from this study.

Connect with a study center

  • Milestone Research Inc.

    London, Ontario N5W 6A2
    Canada

    Site Not Available

  • Stouffville Medical Research Institute Inc.

    Stouffville, Ontario L4A 1H2
    Canada

    Site Not Available

  • Diex Recherche Inc. Division Sherbrooke

    Sherbrooke, Quebec J1L 0H8
    Canada

    Active - Recruiting

  • Northern Light Eastern Maine Medical Center

    Bangor, Maine 04401
    United States

    Site Not Available

  • Northern Light Family Medicine and Residency Center

    Bangor, Maine 04401
    United States

    Site Not Available

  • MaineHealth Pen Bay Hospital

    Rockport, Maine 04856
    United States

    Site Not Available

  • ActivMed Practices and Research

    Methuen, Massachusetts 01844
    United States

    Site Not Available

  • University of Massachusetts Chan Medical School

    Worcester, Massachusetts 01655
    United States

    Active - Recruiting

  • Hunterdon Medical Center

    Flemington, New Jersey 08822
    United States

    Site Not Available

  • IMA Clinical Research Warren

    Warren Township, New Jersey 07059
    United States

    Site Not Available

  • Smith Allergy and Asthma Specialists

    Cortland, New York 13045
    United States

    Active - Recruiting

  • Smith Allergy & Asthma Specialists

    Horseheads, New York 14845
    United States

    Active - Recruiting

  • Altoona Center For Clinical Research

    Duncansville, Pennsylvania 16635
    United States

    Active - Recruiting

  • Allegheny Health and Wellness Pavilion

    Erie, Pennsylvania 16506
    United States

    Active - Recruiting

  • Central Erie Primary Care

    Erie, Pennsylvania 16508
    United States

    Active - Recruiting

  • Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18)

    Pittsburgh, Pennsylvania 15236
    United States

    Active - Recruiting

  • Preferred Primary Care Physicians, Preferred Clinical Research - St.Clair

    Pittsburgh, Pennsylvania 15243
    United States

    Site Not Available

  • Guthrie Medical Group, P.C.

    Sayre, Pennsylvania 18840
    United States

    Site Not Available

  • Robert Packer Hospital

    Sayre, Pennsylvania 18840
    United States

    Active - Recruiting

  • Frontier Clinical Research, LLC

    Scottdale, Pennsylvania 15683
    United States

    Active - Recruiting

  • Northeast Clinical Trials Group

    Scranton, Pennsylvania 18510
    United States

    Active - Recruiting

  • Frontier Clinical Research, LLC

    Smithfield, Pennsylvania 15478
    United States

    Active - Recruiting

  • Preferred Primary Care Physicians

    Uniontown, Pennsylvania 15401
    United States

    Site Not Available

  • Velocity Clinical Research, Providence

    East Greenwich, Rhode Island 02818
    United States

    Site Not Available

  • The University of Vermont Medical Center Inc.

    Burlington, Vermont 05401
    United States

    Site Not Available

  • Amherst Family Practice, P.C.

    Winchester, Virginia 22601
    United States

    Site Not Available

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