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

Recruiting now · Phase 3 · Has a placebo group

Conditions studied: Lyme Disease

In brief

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.

Key facts

Study ID

NCT07500506

Run by

Pfizer

People needed

1712

Starts

2026-04-08

Expected to finish

2026-12-04

Last updated by the study team

2026-05-06

Who can join

Age: 7 and older. Sex: any. Healthy volunteers: accepted.

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.

Where it is running

• Diex Recherche Inc. Division Sherbrooke — Sherbrooke, Quebec, Canada (enrolling)
• Smith Allergy and Asthma Specialists — Cortland, New York, United States (enrolling)
• Smith Allergy & Asthma Specialists — Horseheads, New York, United States (enrolling)
• Altoona Center For Clinical Research — Duncansville, Pennsylvania, United States (enrolling)
• Allegheny Health and Wellness Pavilion — Erie, Pennsylvania, United States (enrolling)
• Central Erie Primary Care — Erie, Pennsylvania, United States (enrolling)
• Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18) — Pittsburgh, Pennsylvania, United States (enrolling)
• Robert Packer Hospital — Sayre, Pennsylvania, United States (enrolling)
• Frontier Clinical Research, LLC — Scottdale, Pennsylvania, United States (enrolling)
• Northeast Clinical Trials Group — Scranton, Pennsylvania, United States (enrolling)
• Frontier Clinical Research, LLC — Smithfield, Pennsylvania, United States (enrolling)
• University of Massachusetts Chan Medical School — Worcester, Massachusetts, United States (enrolling)
• Northern Light Family Medicine and Residency Center — Bangor, Maine, United States
• Amherst Family Practice, P.C. — Winchester, Virginia, United States
• Hunterdon Medical Center — Flemington, New Jersey, United States
• Milestone Research Inc. — London, Ontario, Canada
• Stouffville Medical Research Institute Inc. — Stouffville, Ontario, Canada
• Northern Light Eastern Maine Medical Center — Bangor, Maine, United States
• Preferred Primary Care Physicians — Uniontown, Pennsylvania, United States
• Velocity Clinical Research, Providence — East Greenwich, Rhode Island, United States
• The University of Vermont Medical Center Inc. — Burlington, Vermont, United States
• Preferred Primary Care Physicians, Preferred Clinical Research - St.Clair — Pittsburgh, Pennsylvania, United States

Full record on ClinicalTrials.gov

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