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

Pfizer · NCT07500506

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Opens the official ClinicalTrials.gov record, with the study team’s contacts. Bored Studies doesn’t enroll anyone.

Key facts

Compensation
Not posted. Ask the study team before screening.
Who can join
Ages 7+ · All sexes
Healthy volunteers
Accepted
Study type
Interventional · Phase 3
Target enrollment
1712
US sites recruiting
11
Study start
April 8, 2026
Record last updated
May 6, 2026

Status re-checked against ClinicalTrials.gov within the last 12 hours.

What the study is about

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.

Being studied: VLA15; Placebo

Conditions: Lyme Disease

Eligibility criteria

Copied from the official record. The study team makes the final decision at screening.

Show full criteria

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.

Recruiting US locations

Study contacts (from the official record)

  • Pfizer CT.gov Call Center · 1-800-718-1021 · ClinicalTrials.gov_Inquiries@pfizer.com
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A Study to Learn About the Safety, Tolerability, and… (NCT07500506) | Bored Studies