Lyme DiseasePhase 3NCT05634811
Safety Study of a Vaccine to Help Protect Against Lyme Disease in Healthy Children
A Phase 3 study testing VLA15 and Normal Saline in people with Lyme Disease, run by Pfizer at 65 sites in United States.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 5 to 17 yearsHealthy volunteers can take part
- Conditions the study is for
- Lyme Disease
- What is being tested?
- VLA15 and Normal Saline
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 3,547 participants
- Where
- 65 sitesUnited States
- Study dates
- 12 Dec 2022to 21 Jul 2025
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 5 to 17 years
- All sexes
- Healthy volunteers accepted
- Child
Who may be able to join
- 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.
Who cannot join
- 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.
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- 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.
Trial locations and contacts
65 sites in 1 country.
65 sites in 1 country
United States65 sites
Benchmark Research
Austin, Texas, 78705
Kentucky Pediatric/ Adult Research
Bardstown, Kentucky, 40004
Coast Clinical Research, LLC
Bellflower, California, 90706
Michigan Center of Medical Research (MICHMER)
Bingham Farms, Michigan, 48025
Velocity Clinical Research, Binghamton
Binghamton, New York, 13905
UAB Child Health Research Unit (CHRU)
Birmingham, Alabama, 35233
University of Alabama at Birmingham - School of Medicine
Birmingham, Alabama, 35233
ASR, LLC
Boise, Idaho, 83702
New England Research Associates
Bridgeport, Connecticut, 06606
Buffalo Clinical and Translational Research Center
Buffalo, New York, 14203
Tekton Research, LLC.
Chamblee, Georgia, 30341
Pediatric Research of Charlottesville, LLC
Charlottesville, Virginia, 22902
University of Chicago Medical Center
Chicago, Illinois, 60637
Centricity Research Columbus Ohio Multispecialty
Columbus, Ohio, 43213
Advanced Specialty Care
Commack, New York, 11725
Smith Allergy and Asthma Specialists
Cortland, New York, 13045
Vida Clinical Studies, LLC
Dearborn Heights, Michigan, 48127
Stony Brook Medicine Clinical Research Center
East Setauket, New York, 11733
Upstate Global Health Institute
East Syracuse, New York, 13057
AMR Clinical
El Dorado, Kansas, 67042
Allegheny Health and Wellness Pavilion
Erie, Pennsylvania, 16506
Central Erie Primary Care
Erie, Pennsylvania, 16508
Apex Research Group LLC
Fair Oaks, California, 95628
Benchmark Research
Fort Worth, Texas, 76135
Texas Health Resources
Fort Worth, Texas, 76135
Lakeview Clinical Research
Guntersville, Alabama, 35976
Southampton Hospital
Hampton Bays, New York, 11946
Smith Allergy & Asthma Specialists
Horseheads, New York, 14845
C & R Research Services USA
Houston, Texas, 77022
DM Clinical Research - Kool Kids Pediatrics
Houston, Texas, 77065
Clinical Research Prime
Idaho Falls, Idaho, 83404
Frontier Clinical research
Kingwood, West Virginia, 26537
Preston Healthcare Services
Kingwood, West Virginia, 26537
All Children Pediatrics
Louisville, Kentucky, 40243
Hassman Research Institute
Marlton, New Jersey, 08053
Bio-Medical Research LLC
Miami, Florida, 33144
NYU Langone Hospital - Long Island
Mineola, New York, 11501
Clinical Research Institute
Minneapolis, Minnesota, 55402
Rutgers University
New Brunswick, New Jersey, 08901
Coastal Carolina Research Center
North Charleston, South Carolina, 29405
DiGiovanna Institute for Medical Education & Research
North Massapequa, New York, 11758
Velocity Clinical Research, Omaha
Omaha, Nebraska, 68134
MD Medical Research
Oxon Hill, Maryland, 20745
Preferred Primary Care Physicians, Preferred Clinical Research (Ofc 18)
Pittsburgh, Pennsylvania, 15236
Research Your Health
Plano, Texas, 75093
Clinical Research Prime Rexburg
Rexburg, Idaho, 83440
Clinical Research Partners, LLC
Richmond, Virginia, 23226
Rochester Clinical Research, LLC
Rochester, New York, 14609
Sun Research Institute
San Antonio, Texas, 78215
Northeast Clinical Trials Group
Scranton, Pennsylvania, 18510
White Oak Pediatrics
Silver Spring, Maryland, 20904
Great Lakes Research Institute
Southfield, Michigan, 48075
Sisu BHR
Springfield, Massachusetts, 01103
GCP Research, Global Clinical professionals
St. Petersburg, Florida, 33705
Stamford Therapeutics Consortium
Stamford, Connecticut, 06905
Stony Brook University
Stony Brook, New York, 11794
MOORE Clinical Research, Inc. d/b/a TrueBlue Clinical Research
Tampa, Florida, 33609
ForCare Clinical Research
Tampa, Florida, 33613
Prime Global Research
The Bronx, New York, 10456
Advantage Clinical Trials
The Bronx, New York, 10467
Velocity Clinical Research, Vestal
Vestal, New York, 13850
IMA Clinical Research Warren
Warren Township, New Jersey, 07059
Children's National Medical Center
Washington D.C., District of Columbia, 20010
Velocity Clinical Research, Salt Lake City
West Jordan, Utah, 84088
AMR Clinical
Wichita, Kansas, 67207
About this study
Official title: 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:
Read more
- 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.
- Conditions
- Lyme Disease
- Being tested
- VLA15, Normal Saline
- Keywords
- Borreliosis, Borrelia burgdorferi, Spirochetes, Vector-Borne Disease, Lyme Disease Vaccine, VLA15, Outer Surface Protein A (OspA), Ticks
- Medical subject headings
- Lyme Disease, Borrelia Infections, Vector Borne Diseases
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
VLA15Biological
Also called PF-07307405
6-valent OspA-based Lyme disease vaccine
Normal SalineOther
0.9% sodium chloride solution for injection
| Study group | Role | What they receive |
|---|---|---|
| VLA15 | Experimental | Participants will receive 6-valent OspA-based Lyme disease vaccine (VLA15). Receives: Biological: VLA15 |
| Normal Saline (Placebo) | Placebo comparator | Participants will receive 0.9% sodium chloride solution for injection Receives: Other: Normal Saline |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: 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.
Measured: Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Dec 2022
- Study start12 Dec 2022
- Primary completion21 Jul 2025
- Study completion21 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Lyme DiseaseStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 3,547 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05634811
- Sponsor's protocol ID
- C4601012
- Other IDs
- NCT05634811, 2025-000441-15, 2025
- Status last verified
- Apr 2026
- First submitted
- 22 Nov 2022
- Last updated
- 7 May 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: 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.
Study at a glance
From the registry record, last updated by the sponsor on 7 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT05634811
- Acronym / sponsor ID
- C4601012
- Conditions
- Lyme Disease
- Keywords
- Borreliosis, Borrelia burgdorferi, Spirochetes, Vector-Borne Disease, Lyme Disease Vaccine, VLA15, Outer Surface Protein A (OspA), Ticks
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 3,547 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 12 Dec 2022 (actual)
- Primary completion
- 21 Jul 2025 (actual)
- Study completion
- 21 Jul 2025 (actual)
- First posted
- 2 Dec 2022 (actual)
- Results
- Posted 7 May 2026
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| VLA15 | Experimental | Biological: VLA15Participants will receive 6-valent OspA-based Lyme disease vaccine (VLA15). |
| Normal Saline (Placebo) | Placebo comparator | Other: Normal SalineParticipants will receive 0.9% sodium chloride solution for injection |
Who may qualify
- Ages
- 5 to 17 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
Key inclusion criteria (2 listed)
- 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.
Key exclusion criteria (15 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| VLA15Also: PF-073074056-valent OspA-based Lyme disease vaccine | Biological | VLA15 |
| Normal Saline0.9% sodium chloride solution for injection | Other | Normal Saline (Placebo) |
Primary outcome
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 1
Time frame: From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)
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.
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 2
Time frame: From Day 1 through Day 7 after Study Vaccination 2 (Vaccination on Day 1, Month 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.
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 3
Time frame: From Day 1 through Day 7 after Study Vaccination 3 (Vaccination on Day 1, Month 6)
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.
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 4 (Booster Dose)
Time frame: From Day 1 through Day 7 after Study Vaccination 4 (Vaccination on Day 1, Month 18)
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.
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days After Any Study Vaccination
Time frame: From Day 1 through Day 7 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.
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 1
Time frame: From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)
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.
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 2
Time frame: From Day 1 through Day 7 after Study Vaccination 2 (Vaccination on Day 1, Month 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.
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 3
Time frame: From Day 1 through Day 7 after Study Vaccination 3 (Vaccination on Day 1, Month 6)
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.
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days Following Study Vaccination 4 (Booster Dose)
Time frame: From Day 1 through Day 7 after Study Vaccination 4 (Vaccination on Day 1, Month 18)
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.
Percentage of Participants With at Least 1 Systemic Event of Any Grade for up to 7 Days After Any Study Vaccination
Time frame: From Day 1 through Day 7 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.
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 1
Time frame: From Day 1 through 1 Month after Study Vaccination 1 (Vaccination on Day 1, Month 0)
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.
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 2
Time frame: From Day 1 through 1 Month after Study Vaccination 2 (Vaccination on Day 1, Month 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.
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 3
Time frame: From Day 1 through 1 Month after Study Vaccination 3 (Vaccination on Day 1, Month 6)
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.
Percentage of Participants With AEs Through 1 Month Following Study Vaccination 4 (Booster Dose)
Time frame: From Day 1 through 1 Month after Study Vaccination 4 (Vaccination on Day 1, Month 18)
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.
Percentage of Participants With AEs Through 1 Month Following Any Study Vaccination
Time frame: From Day 1 through 1 Month after 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.
Percentage of Participants With Newly Diagnosed Chronic Medical Condition (NDCMCs) Throughout the Study
Time frame: Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)
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.
Percentage of Participants With Serious Adverse Events (SAEs) Throughout the Study
Time frame: Throughout the study (from study vaccination 1 through 6 months post study Vaccination 4 [Booster dose]: maximum up to 24 months)
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.
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 May 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. 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.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
65 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing VLA15 and Normal Saline in people with Lyme Disease, run by Pfizer at 65 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 7 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 65 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 7 May 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percentage of Participants With at Least 1 Local Reaction of Any Grade for up to 7 Days Following Study Vaccination 1 (time frame: From Day 1 through Day 7 after Study Vaccination 1 (Vaccination on Day 1, Month 0)). The study lists 17 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 7 May 2026.