Safety Study of a Vaccine to Help Protect Against Lyme Disease in Healthy Children

A PHASE 3, RANDOMIZED, PLACEBO-CONTROLLED, OBSERVER-BLINDED TRIAL TO EVALUATE THE SAFETY OF A 6-VALENT OspA-BASED LYME DISEASE VACCINE (VLA15) IN HEALTHY CHILDREN 5 THROUGH 17 YEARS OF AGE

This study is to understand if the study vaccine (called VLA15) is safe in healthy children.

We are looking for children who:

• are healthy
• are age 5 through 17
• have not been diagnosed with any form of Lyme disease in the past
• have not received any vaccines for Lyme disease in the past

Lyme disease happens most often in children of this age. The study vaccine may be used potentially to help prevent Lyme disease. The goal of this study is to get more information about the safety of the study vaccine in this age group.

Participants will be in this study for about 2 years. During that time, they will receive VLA15 or placebo (sterile saltwater solution) by a "shot" in the arm. We will compare experience of children receiving VLA15 to those receiving the placebo. Participants will not know whether they get VLA15 or placebo.

Everyone participating in this study will:

• get the shots in a clinic or in a hospital office
• receive a total of 4 shots
• receive the first 3 shots within 6 months
• receive the last shot about 1 year afterwards
• need to come to the trial site for 6 planned visits; 4 of these are vaccination visits and 2 are follow-up visits. We will contact you by phone 1 time every year during the study to monitor your experience. You may have extra visits if you experience a severe reaction after a vaccine dose.

Study Overview

• Status: Completed
• Conditions: Lyme Disease
• Intervention / Treatment: Biological: VLA15; Other: Normal Saline

• Study Type: Interventional
• Enrollment (Actual): 3547
• Phase: Phase 3

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35233
      • University of Alabama at Birmingham - School of Medicine
    • Birmingham, Alabama, United States, 35233
      • UAB Child Health Research Unit (CHRU)
    • Guntersville, Alabama, United States, 35976
      • Lakeview Clinical Research
  • California
    • Bellflower, California, United States, 90706
      • Coast Clinical Research, LLC
    • Fair Oaks, California, United States, 95628
      • Apex Research Group LLC
  • Connecticut
    • Bridgeport, Connecticut, United States, 06606
      • New England Research Associates
    • Stamford, Connecticut, United States, 06905
      • Stamford Therapeutics Consortium
  • District of Columbia
    • Washington D.C., District of Columbia, United States, 20010
      • Children's National Medical Center
  • Florida
    • Miami, Florida, United States, 33144
      • Bio-Medical Research LLC
    • St. Petersburg, Florida, United States, 33705
      • GCP Research, Global Clinical professionals
    • Tampa, Florida, United States, 33613
      • ForCare Clinical Research
    • Tampa, Florida, United States, 33609
      • MOORE Clinical Research, Inc. d/b/a TrueBlue Clinical Research
  • Georgia
    • Chamblee, Georgia, United States, 30341
      • Tekton Research, LLC.
  • Idaho
    • Boise, Idaho, United States, 83702
      • ASR, LLC
    • Idaho Falls, Idaho, United States, 83404
      • Clinical Research Prime
    • Rexburg, Idaho, United States, 83440
      • Clinical Research Prime Rexburg
  • Illinois
    • Chicago, Illinois, United States, 60637
      • University of Chicago Medical Center
  • Kansas
    • El Dorado, Kansas, United States, 67042
      • AMR Clinical
    • Wichita, Kansas, United States, 67207
      • AMR Clinical
  • Kentucky
    • Bardstown, Kentucky, United States, 40004
      • Kentucky Pediatric/ Adult Research
    • Louisville, Kentucky, United States, 40243
      • All Children Pediatrics
  • Maryland
    • Oxon Hill, Maryland, United States, 20745
      • MD Medical Research
    • Silver Spring, Maryland, United States, 20904
      • White Oak Pediatrics
  • Massachusetts
    • Springfield, Massachusetts, United States, 01103
      • Sisu BHR
  • Michigan
    • Bingham Farms, Michigan, United States, 48025
      • Michigan Center of Medical Research (MICHMER)
    • Dearborn Heights, Michigan, United States, 48127
      • Vida Clinical Studies, LLC
    • Southfield, Michigan, United States, 48075
      • Great Lakes Research Institute
  • Minnesota
    • Minneapolis, Minnesota, United States, 55402
      • Clinical Research Institute
  • Nebraska
    • Omaha, Nebraska, United States, 68134
      • Velocity Clinical Research, Omaha
  • New Jersey
    • Marlton, New Jersey, United States, 08053
      • Hassman Research Institute
    • New Brunswick, New Jersey, United States, 08901
      • Rutgers University
    • Warren Township, New Jersey, United States, 07059
      • IMA Clinical Research Warren
  • New York
    • Binghamton, New York, United States, 13905
      • Velocity Clinical Research, Binghamton
    • Buffalo, New York, United States, 14203
      • Buffalo Clinical and Translational Research Center
    • Commack, New York, United States, 11725
      • Advanced Specialty Care
    • Cortland, New York, United States, 13045
      • Smith Allergy and Asthma Specialists
    • East Setauket, New York, United States, 11733
      • Stony Brook Medicine Clinical Research Center
    • East Syracuse, New York, United States, 13057
      • Upstate Global Health Institute
    • Hampton Bays, New York, United States, 11946
      • Southampton Hospital
    • Horseheads, New York, United States, 14845
      • Smith Allergy & Asthma Specialists
    • Mineola, New York, United States, 11501
      • NYU Langone Hospital - Long Island
    • North Massapequa, New York, United States, 11758
      • DiGiovanna Institute for Medical Education & Research
    • Rochester, New York, United States, 14609
      • Rochester Clinical Research, LLC
    • Stony Brook, New York, United States, 11794
      • Stony Brook University
    • The Bronx, New York, United States, 10456
      • Prime Global Research
    • The Bronx, New York, United States, 10467
      • Advantage Clinical Trials
    • Vestal, New York, United States, 13850
      • Velocity Clinical Research, Vestal
  • Ohio
    • Columbus, Ohio, United States, 43213
      • Centricity Research Columbus Ohio Multispecialty
  • Pennsylvania
    • Erie, Pennsylvania, United States, 16506
      • Allegheny Health and Wellness Pavilion
    • Erie, Pennsylvania, United States, 16508
      • Central Erie Primary Care
    • Pittsburgh, Pennsylvania, United States, 15236
      • Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18)
    • Scranton, Pennsylvania, United States, 18510
      • Northeast Clinical Trials Group
  • South Carolina
    • North Charleston, South Carolina, United States, 29405
      • Coastal Carolina Research Center
  • Texas
    • Austin, Texas, United States, 78705
      • Benchmark Research
    • Fort Worth, Texas, United States, 76135
      • Benchmark Research
    • Fort Worth, Texas, United States, 76135
      • Texas Health Resources
    • Houston, Texas, United States, 77022
      • C & R Research Services USA
    • Houston, Texas, United States, 77065
      • DM Clinical Research - Kool Kids Pediatrics
    • Plano, Texas, United States, 75093
      • Research Your Health
    • San Antonio, Texas, United States, 78215
      • Sun Research Institute
  • Utah
    • West Jordan, Utah, United States, 84088
      • Velocity Clinical Research, Salt Lake City
  • Virginia
    • Charlottesville, Virginia, United States, 22902
      • Pediatric Research of Charlottesville, LLC
    • Richmond, Virginia, United States, 23226
      • Clinical Research Partners, LLC
  • West Virginia
    • Kingwood, West Virginia, United States, 26537
      • Frontier Clinical Research
    • Kingwood, West Virginia, United States, 26537
      • Preston Healthcare Services

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 5 years to 17 years (Child)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy participants at enrollment who are determined to be eligible for inclusion in the study. Participants with preexisting chronic medical conditions determined to be stable may be included.
• Participants and/or participants' parent(s)/guardian who are willing and able to comply with all scheduled visits, study procedures and lifestyle considerations for the duration of the study.

Exclusion Criteria:

• Female participants that are pregnant, breastfeeding, or have a positive urine pregnancy test at Visit 1. Sexually active females and fertile males unwilling to use contraception as per protocol.
• Any contraindication to vaccination or vaccine components, including previous anaphylactic reaction to any vaccine or vaccine-related components.
• Any diagnosis of Lyme disease within the past 3 months.
• Any history of Lyme arthritis, carditis, neuroborreliosis, or other disseminated Lyme Disease (LD), regardless of when diagnosed.
• Known tick bite within the past 4 weeks.
• Congenital or acquired immunodeficiency or other conditions or treatments associated with immunosuppression that would inhibit the ability to mount an immune response to a vaccine.
• Other medical, psychiatric condition, active suicidal ideation/behavior or lab abnormality which increases risk of study participation or, in investigator's judgment is inappropriate for the study.
• Receipt of a previous vaccination for LD.
• Treatment for LD in the 3 months prior to study intervention administration.
• Receipt of blood/plasma products or immunoglobulins within 6 months before study intervention administration through conclusion of the study.
• Receipt of systemic corticosteroids for ≥14 days within 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical corticosteroids are permitted.
• Receipt of chronic systemic treatment with other known immunosuppressant medications, or radiotherapy, within 6 months before study intervention administration.
• Current use of any prohibited concomitant medication(s) or participants unwilling/unable to use a permitted concomitant medication(s).
• Participation in other studies involving investigational drugs/vaccines/devices within 28 days prior to study entry and/or during study participation (observational studies are acceptable).
• Investigator site staff, sponsor/sponsor delegates directly involved in the conduct of the study and their family members; site staff supervised by the investigator and their family members.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: VLA15; Participants will receive 6-valent OspA-based Lyme disease vaccine (VLA15).	Biological: VLA15; 6-valent OspA-based Lyme disease vaccine; Other Names: PF-07307405
Placebo Comparator: Normal Saline (Placebo); Participants will receive 0.9% sodium chloride solution for injection	Other: Normal Saline; 0.9% sodium chloride solution for injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 1	Local reactions included pain at injection site, redness and swelling and were recorded by participants in the electronic dairy (e-diary) or by investigators in case report form (CRF) after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on Center for Biologics Evaluation and Research (CBER) toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 2	Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 2 (Vaccination on Day 1, Month 2)
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 3	Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 3 (Vaccination on Day 1, Month 6)
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 4 (Booster Dose)	Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 4 (Vaccination on Day 1, Month 18)
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days After Any Study Vaccination	Local reactions included pain at injection site, redness and swelling and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Local reactions were graded per the 'Local Reaction Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 local reaction of any grade were reported in this outcome measure.	From Day 1 through Day 7 after any study vaccination
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 1	Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 2	Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 2 (Vaccination on Day 1, Month 2)
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 3	Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 3 (Vaccination on Day 1, Month 6)
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 4 (Booster Dose)	Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.	From Day 1 through Day 7 after Study Vaccination 4 (Vaccination on Day 1, Month 18)
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days After Any Study Vaccination	Systemic events included fever, fatigue, headache, muscle pain and joint pain and were recorded by participants in the e-diary or by investigators in CRF after vaccination. Systemic events were graded per the 'Systemic Events Grading Scale' per protocol based on CBER toxicity guidelines. Percentage of participants with at least 1 systemic event of any grade were reported in this outcome measure.	From Day 1 through Day 7 after any study vaccination
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 1	An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 1 were included in this outcome measure. AEs included both serious AEs (SAEs) and non-SAEs.	From Day 1 through 1 Month after Study Vaccination 1 (Vaccination on Day 1, Month 0)
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 2	An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 2 were included in this outcome measure. AEs included both SAEs and non-SAEs.	From Day 1 through 1 Month after Study Vaccination 2 (Vaccination on Day 1, Month 2)
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 3	An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 3 were included in this outcome measure. AEs included both SAEs and non-SAEs.	From Day 1 through 1 Month after Study Vaccination 3 (Vaccination on Day 1, Month 6)
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 4 (Booster Dose)	An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after dose 4 were included in this outcome measure. AEs included both SAEs and non-SAEs.	From Day 1 through 1 Month after Study Vaccination 4 (Vaccination on Day 1, Month 18)
Percentage of Participants With AEs Through 1 Month Following Any Study Vaccination	An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (excluding local reactions and systematic events) after any dose were included in this outcome measure.	From Day 1 through 1 Month after any study vaccination
Percentage of Participants With Newly Diagnosed Chronic Medical Condition (NDCMCs) Throughout the Study	An NDCMC was defined as a disease or medical condition, not previously identified, that was expected to be persistent or was otherwise long-lasting in its effects. NDCMCs included conditions that were undiagnosed prior to study entry (diagnosed while in the study and confirmed not to be a preexisting condition) and that were not considered temporary conditions based upon the expected natural history of the condition. An NDCMC was not reported on AE CRF.	Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)
Percentage of Participants With Serious Adverse Events (SAEs) Throughout the Study	An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria: resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect, any other important medical event.	Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)

Collaborators and Investigators

• Sponsor: Pfizer
• Investigators: Study Director: Pfizer CT.gov Call Center, Pfizer

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start (Actual): December 12, 2022
• Primary Completion (Actual): July 21, 2025
• Study Completion (Actual): July 21, 2025

Study Registration Dates

• First Submitted: November 22, 2022
• First Submitted That Met QC Criteria: November 22, 2022
• First Posted (Actual): December 2, 2022

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: April 14, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Ticks; Borreliosis; Borrelia burgdorferi; Spirochetes; Vector-Borne Disease; Lyme Disease Vaccine; VLA15; Outer Surface Protein A (OspA)
• Additional Relevant MeSH Terms: Infections; Bacterial Infections; Bacterial Infections and Mycoses; Gram-Negative Bacterial Infections; Spirochaetales Infections; Tick-Borne Diseases; Vector Borne Diseases; Lyme Disease; Borrelia Infections; Pharmaceutical Preparations; Crystalloid Solutions; Isotonic Solutions; Solutions; Saline Solution
• Other Study ID Numbers: C4601012; NCT05634811 (Registry Identifier: ClinicalTrials.gov); 2025-000441-15 (EudraCT Number)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No