A Study to Learn About the Safety, Tolerability, and Immunogenicity of a Fifth Dose of 6-Valent OspA-Based Lyme Disease Vaccine
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
1 other identifier
interventional
1,712
2 countries
22
Brief 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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_3
Started Apr 2026
Shorter than P25 for phase_3
22 active sites
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
March 23, 2026
CompletedFirst Posted
Study publicly available on registry
March 30, 2026
CompletedStudy Start
First participant enrolled
April 8, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
December 4, 2026
ExpectedStudy Completion
Last participant's last visit for all outcomes
December 4, 2026
May 6, 2026
May 1, 2026
8 months
March 23, 2026
May 4, 2026
Conditions
Outcome Measures
Primary Outcomes (7)
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)
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.
At 1 month after completion of Dose 5
Sero-response of anti-OspA IgG concentrations for each serotype (ST1-ST6).
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.
At 1 month after completion of Dose 5
Secondary Outcomes (9)
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5
Geometric mean ratio (GMR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At 1 month after completion of Dose 5
Geometric mean fold rise (GMFR) of anti-OspA IgG concentrations for each serotype (ST1-ST6)
At just prior to Dose 5 and 1 month after completion of Dose 5
- +4 more secondary outcomes
Study Arms (4)
VLA15-1A
EXPERIMENTALParticipants will receive a single injection in the muscle (IM) of VLA15 at Visits 1, two years after their 4th dose of VLA15
VLA15-1B
PLACEBO COMPARATORParticipants will receive a single injection in the muscle (IM) of Saline at Visits 1, two years after their 4th dose of VLA15
VLA15-2A
EXPERIMENTALParticipants will receive a single injection in the muscle (IM) of VLA15 at Visits 1, one year after their 4th dose of VLA15
VLA15-2B
PLACEBO COMPARATORParticipants will receive a single injection in the muscle (IM) of saline at Visits 1, one year after their 4th dose of VLA15
Interventions
Eligibility Criteria
You may qualify if:
- 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.
You may not qualify if:
- 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.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
- Pfizerlead
Study Sites (22)
Northern Light Eastern Maine Medical Center
Bangor, Maine, 04401, United States
Northern Light Family Medicine and Residency Center
Bangor, Maine, 04401, United States
University of Massachusetts Chan Medical School
Worcester, Massachusetts, 01655, United States
Hunterdon Medical Center
Flemington, New Jersey, 08822, United States
Smith Allergy and Asthma Specialists
Cortland, New York, 13045, United States
Smith Allergy & Asthma Specialists
Horseheads, New York, 14845, United States
Altoona Center For Clinical Research
Duncansville, Pennsylvania, 16635, United States
Allegheny Health and Wellness Pavilion
Erie, Pennsylvania, 16506, United States
Central Erie Primary Care
Erie, Pennsylvania, 16508, United States
Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18)
Pittsburgh, Pennsylvania, 15236, United States
Preferred Primary Care Physicians, Preferred Clinical Research - St.Clair
Pittsburgh, Pennsylvania, 15243, United States
Robert Packer Hospital
Sayre, Pennsylvania, 18840, United States
Frontier Clinical Research, LLC
Scottdale, Pennsylvania, 15683, United States
Northeast Clinical Trials Group
Scranton, Pennsylvania, 18510, United States
Frontier Clinical Research, LLC
Smithfield, Pennsylvania, 15478, United States
Preferred Primary Care Physicians
Uniontown, Pennsylvania, 15401, United States
Velocity Clinical Research, Providence
East Greenwich, Rhode Island, 02818, United States
The University of Vermont Medical Center Inc.
Burlington, Vermont, 05401, United States
Amherst Family Practice, P.C.
Winchester, Virginia, 22601, United States
Milestone Research Inc.
London, Ontario, N5W 6A2, Canada
Stouffville Medical Research Institute Inc.
Stouffville, Ontario, L4A 1H2, Canada
Diex Recherche Inc. Division Sherbrooke
Sherbrooke, Quebec, J1L 0H8, Canada
Related Links
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Pfizer CT.gov Call Center
Pfizer
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 3
- Allocation
- RANDOMIZED
- Masking
- TRIPLE
- Who Masked
- PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
- Masking Details
- Third-party blind unblinded
- Purpose
- PREVENTION
- Intervention Model
- PARALLEL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
March 23, 2026
First Posted
March 30, 2026
Study Start
April 8, 2026
Primary Completion (Estimated)
December 4, 2026
Study Completion (Estimated)
December 4, 2026
Last Updated
May 6, 2026
Record last verified: 2026-05
Data Sharing
- IPD Sharing
- Will share
Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.