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Active, Not Recruiting

NCT Number: NCT07226882

A Study to Learn About Different Dosing Schedules of a Lyme Disease Vaccine in Healthy Adults

The purpose of this study is to learn about the safety and effects of the Lyme disease vaccine (called VLA15) when given at different time points.

This study is seeking participants who:

* are generally healthy and between 18 and 44 years of age, * have never had a vaccine for Lyme disease before, * are not currently taking, or haven't recently taken, medicines like chemotherapy, blood products, or blood thinners, and * 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 5 doses through a shot in the upper arm. Four doses will be the study vaccine (VLA15), and 1 dose will be saltwater.

The study will compare the experiences of people receiving the study vaccine at different time points. This will help see if the study vaccine is safe and will help understand its effect on the body.

Participants will take part in this study for about 2 years. During this time, the participants will have 11 planned visits - 8 will be at the study clinic and 3 will be done over the phone. The clinic visits may include having a health check, giving a small amount of blood (about 20 mL or 4 teaspoons), and getting the study vaccine or saltwater as a shot.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Lyme Borreliosis Bacterial Infections Bacterial Infections and Mycoses Borrelia Infections Central Nervous System Bacterial Infections Central Nervous System Diseases Central Nervous System Infections Gram-Negative Bacterial Infections Infections Lyme Disease Lyme Neuroborreliosis Nervous System Diseases Spirochaetales Infections Tick-Borne Diseases Vector Borne Diseases

Age range

18 year–44 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

IMA Clinical Research Warren, Warren Township, New Jersey, United States

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About this study

This is a Phase 3, randomized, parallel-group, placebo-controlled, double-blinded (third-party unblinded) study to evaluate the safety, tolerability, and immunogenicity of different vaccination schedules of the 6-valent OspA-based Lyme disease (LD) vaccine, VLA15, in healthy participants 18 through 44 years of age.

Participants will be randomized in a 1:1:1:1 ratio to 1 of the 4 parallel study groups. Each participant will receive 4 doses of VLA15 and 1 dose of placebo (saline) at different time points. This study will use an external data monitoring committee (EDMC). The EDMC is independent of the Pfizer study team and includes only external members. The EDMC charter describes the role of the EDMC in more detail.

Approximately 200 participants will be enrolled in the study.

Healthy individuals 18 through 44 years of age who are willing to comply with all study procedures and provide signed informed consent will be enrolled. Pregnant or breastfeeding individuals and fertile individuals who are unwilling or unable to use effective contraceptive methods as outlined in this protocol will not be enrolled. Individuals who have contraindication to vaccination, conditions or treatments that can inhibit the ability to mount an immune response to a vaccine, or other conditions that may increase the risk of study participation will be excluded from this study. Individuals who have previously received a licensed or investigational vaccine for LD will also be excluded from this study.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

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.
  • Any prior Lyme disease vaccination, or recent or concurrent participation in a separate interventional study.
  • Staff or direct family of the study site staff and Sponsor.

Treatment and study plan

VLA15

Biological

Participants will receive IM injection of 6-valent OspA-based Lyme disease vaccine

Placebo

Biological

Saline

Primary outcomes

  1. Geometric Mean Concentration (GMC) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG)

    Time frame: At 1 month after the fourth VLA15 dose

  2. Geometric Mean Fold Rise (GMFR) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations

    Time frame: Before the first dose to 1 month after the fourth VLA15 dose

  3. Sero-Response Rate Based on Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations.

    Time frame: Before the first dose to 1 month after the fourth VLA15 dose

  4. Percentage of Participants With Local Reactions For Each Group

    Time frame: Within 7 days after each vaccination

  5. Percentage of Participants With Systemic Events For Each Group

    Time frame: Within 7 days after each vaccination

  6. Percentage of Participants With Adverse Events (AEs) For Each Group

    Time frame: Within 1 month after each vaccination

  7. Percentage of Participants With Serious Adverse Events (SAEs) For Each Group

    Time frame: From the time the participant provides informed consent up to approximately 6 months after the last vaccination

  8. Percentage of Participants With Newly Diagnosed Chronic Medical Conditions (NDCMCs) For Each Group

    Time frame: From the time the participant provides informed consent up to approximately 6 months after the last vaccination

Secondary outcomes

  1. Geometric Mean Concentration (GMC) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG)

    Time frame: At 1 month after the third VLA15 dose

  2. Geometric Mean Fold Rise (GMFR) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations

    Time frame: Before the first dose to 1 month after the third VLA15 dose

  3. Sero-Response Rate Based on Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations.

    Time frame: Before the first dose to 1 month after the third VLA15 dose

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Registry information

Official study title

A PHASE 3, PLACEBO-CONTROLLED, DOUBLE-BLINDED, RANDOMIZED STUDY TO EVALUATE THE SAFETY, TOLERABILITY, AND IMMUNOGENICITY OF DIFFERENT VACCINATION SCHEDULES OF 6-VALENT OSPA-BASED LYME DISEASE VACCINE, VLA15, IN HEALTHY ADULT PARTICIPANTS

Important dates

Study start
2025
Primary completion
2028
Study completion
2028
First posted
Nov 12, 2025
Registry last updated
May 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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