Under construction – not a live service
Sign in
Taking people in CanadaPhase 3

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

Key facts

Where
London, Sherbrooke, and Stouffville, CanadaSee the 3 sites
Phase
Phase 3

Where in Canada

  • Milestone Research Inc.London, CanadaNot yet recruiting
  • Diex Recherche Inc. Division SherbrookeSherbrooke, CanadaTaking people
  • Stouffville Medical Research Institute Inc.Stouffville, CanadaNot yet recruiting

Questions to ask the study team

  1. How often do I need to come in, and for how long each time?
  2. Are travel costs paid?
  3. Can I keep my own doctor?
  4. What happens if I want to stop?

Contact the study team: see the registry record → Contacts and Locations

Print a page for my doctor

Trial details

Who runs it
Pfizer
Trial code
NCT07500506
Record updated
6 May 2026
Original description
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.Read full original descriptionShow less

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

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.

Inclusion: 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: Recent or concurrent participation in a separate interventional study; 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; Pregnant or breastfeeding participants; Staff or direct family of the study site staff and Sponsor.

ClinicalTrials.gov NCT07500506