Fifth dose of the 6‑valent OspA Lyme vaccine (VLA15)

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This is a randomized, double‑blind, placebo‑controlled Phase 3 trial that enrolls about 1,712 healthy participants aged 7 years and older who previously received four doses of VLA15. Participants are randomized 5:1 to receive a single injection of VLA15 or saline placebo at the first visit, with safety, tolerability, and immune responses followed over about 12 months. Study visits include collection of blood samples (including a required post‑dose‑4 sample from the prior study), physical exams, and safety monitoring across four planned clinic visits. An independent external data monitoring committee (EDMC) provides oversight of participant safety during the trial.

Why it matters

Who can join: the full rules

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.

Where it's running

• University of Massachusetts Chan Medical School
  Worcester, Massachusetts, United States Recruiting
• Smith Allergy and Asthma Specialists
  Cortland, New York, United States Recruiting
• Smith Allergy & Asthma Specialists
  Horseheads, New York, United States Recruiting
• Altoona Center For Clinical Research
  Duncansville, Pennsylvania, United States Recruiting
• Allegheny Health and Wellness Pavilion
  Erie, Pennsylvania, United States Recruiting
• Central Erie Primary Care
  Erie, Pennsylvania, United States Recruiting

Study contacts

• Study coordinator: Pfizer CT.gov Call Center
• Email: ClinicalTrials.gov_Inquiries@pfizer.com
• Phone: 1-800-718-1021

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.