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Completed

NCT Number: NCT05477524

An Efficacy, Safety, Tolerability, Immunogenicity, and Lot-Consistency Clinical Trial of a 6-Valent OspA-Based Lyme Disease Vaccine (VLA15)

The main purpose of this clinical study is to evaluate a 6-valent OspA-based Lyme disease vaccine (VLA15) for prevention of Lyme disease within North America and Europe. Approximately 9,400 healthy participants (this number excludes participants from 8 sites which were terminated for quality issues) 5 years and older will be recruited from areas with high levels of endemic Lyme disease to receive VLA15 or placebo (an inactive substance consisting of saltwater). Each participant will have about a 50% chance of receiving VLA15 and about a 50% chance of receiving placebo. A subset of participants will receive VLA15 from 3 different lots or placebo (1:1:1:3 ratio) to assess lot equivalence.

Participants will receive a 3-dose primary vaccination series at about 0, 2, and 5 to 9 months and then receive a booster dose about 12 months after end of primary vaccination series. Vaccination of participants will occur at a time of year such that the primary series is completed before the peak Lyme disease season followed by a booster dose just prior to the beginning of the second Lyme disease season. A subset of participants will be followed for a third Lyme disease season.

Comparison will be made between the Lyme disease cases of people receiving the study vaccine to those of the people who are not. This will help us determine if the study vaccine is safe and effective.

If enrolled, participants will need to visit the research site at least 7 times during the study, and for a subset of participants up to 9 times. There will also be at least 5 telephone contacts. It is expected that each participant will take part in this study for up to about 2 and a half years. The subset of participants followed for a third Lyme disease season will take part in this study for up to about to 3 and a half years.

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Key information

Conditions

Lyme Disease Bacterial Infections Bacterial Infections and Mycoses Borrelia Infections Gram-Negative Bacterial Infections Infections Spirochaetales Infections Tick-Borne Diseases Vector Borne Diseases

Age range

5 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Viable Clinical Research Corporation, Bridgewater, Nova Scotia, Canada

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Who can participate

Healthy volunteers accepted: Yes

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

Key Inclusion Criteria:

  • Participants who reside in areas with endemic Lyme disease and who lead lifestyles that put them at increased risk for Lyme disease. For example, this could include, but not be limited to:
  • Individuals who work in B burgdorferi-infected/tick-infested areas, especially those with occupations that may be associated with higher risk of exposure, such as landscaping, forestry, and wildlife and parks management.
  • Individuals who pursue recreational activities such as hiking, camping, fishing, hunting, jogging, or gardening in such areas.
  • Individuals who live on land plots with tree lines and come into contact with these trees regularly.
  • Individuals who have dogs that regularly are outdoors and frequently return with attached ticks.
  • Individuals who participate in activities in areas with tall grass, smaller wooded areas beside forests, open fields, lakesides, and riversides.

Key Exclusion Criteria:

  • Any female participants that are pregnant (or have a positive urine pregnancy test) or are breastfeeding.
  • Any diagnosis of Lyme disease within the past 3 months.
  • Any history of Lyme carditis, neuroborreliosis, or arthritis, or other disseminated Lyme disease regardless of when diagnosed.
  • Known tick bite within the past 4 weeks.
  • Newly developed or unstable underlying conditions that may interfere with the assessment of Lyme disease, including but not limited to chronic arthralgia/arthritis, second/third-degree AV heart block, chronic pain syndromes, and chronic skin conditions that reduce the ability to detect cutaneous manifestations of Lyme disease.
  • Any unstable autoimmune condition with a manifestation (eg, arthritic and neurologic) that may interfere with the assessment of Lyme disease.
  • Chronic systemic doxycycline or minocycline or other tetracycline class drug use for acne or any other chronic suppressive antibiotics used to treat other conditions.

Treatment and study plan

VLA15

Biological

Shot in the deltoid muscle (preferable in the nondominant arm)

Saline

Other

Shot in the deltoid muscle (preferable in the nondominant arm)

Primary outcomes

  1. Relative incidence rate reduction of confirmed Lyme disease cases in the VLA15 group compared to the placebo group

    Time frame: Beginning 1 month after receiving the booster dose (28 days after receiving the booster dose through the end of the Lyme disease season following the booster dose (end of October)).

    A confirmed case of Lyme disease, caused by B burgdorferi sensu lato, is defined as a clinically suspected case of Lyme disease that is confirmed by PCR, culture, microbial cell-free B burgdorferi-specific DNA sequencing, or serological antiborrelial antibody assay, and finally assessed and confirmed to be a case by the independent Adjudication Committee

  2. Percentage of participants reporting local reactions

    Time frame: Within 7 days following each study intervention administration

  3. Percentage of participants reporting systemic events

    Time frame: Within 7 days following each study intervention administration

  4. Percentage of participants reporting adverse events (AEs)

    Time frame: Through 1 month following each study intervention administration

  5. Percentage of participants reporting newly diagnosed chronic medical conditions (NDCMCs)

    Time frame: Through study completion, up to approximately 42 months.

  6. Percentage of participants reporting serious adverse events (SAEs)

    Time frame: Through study completion, up to approximately 42 months.

  7. Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 1 to Lot 2

    Time frame: At 1 month after completion of the primary series and the booster dose

  8. Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 1 to Lot 3

    Time frame: At 1 month after completion of the primary series and the booster dose

  9. Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6) for Lot 2 to Lot 3

    Time frame: At 1 month after completion of the primary series and the booster dose

  10. Geometric mean ratio (GMR) of anti-OspA titers for each serotype (ST1-ST6)

    Time frame: At 1 month after completion of the booster dose

    Immunobridging objective to determine non-inferiority between 5-17 year old and 18-44 year old participant strata using GMRs 1 month after completion of booster dose.

  11. Sero-response of anti-OspA IgG concentrations for each serotype (ST1-ST6)

    Time frame: At 1 month after completion of the booster dose

    Immunobridging objective to determine non-inferiority between 5-17 year old and 18-44 year old participant strata using difference in seroresponse rates 1 month after completion of booster dose.

Secondary outcomes

  1. Vaccine efficacy among participants enrolled from North American sites

    Time frame: Through the end of the Lyme disease season beginning 1 month after receiving the booster dose (28 days after completion of the booster dose until end of October)

    A confirmed case of Lyme disease, caused by B burgdorferi sensu lato, is defined as a clinically suspected case of Lyme disease that is confirmed by PCR, culture, microbial cell-free B burgdorferi-specific DNA sequencing, or serological antiborrelial antibody assay, and finally assessed and confirmed to be a case by the independent Adjudication Committee

  2. Vaccine efficacy among participants after primary series

    Time frame: Through the end of the Lyme disease season beginning 1 month after completing the primary series (28 days after completion of the primary series until end of October)

    A confirmed case of Lyme disease, caused by B burgdorferi sensu lato, is defined as a clinically suspected case of Lyme disease that is confirmed by PCR, culture, microbial cell-free B burgdorferi-specific DNA sequencing, or serological antiborrelial antibody assay, and finally assessed and confirmed to be a case by the independent Adjudication Committee

Sponsors and collaborators

Lead sponsor

Pfizer

Industry

Collaborators

  • Valneva Austria GmbH

Registry information

Official study title

A PHASE 3, MULTICENTER, PLACEBO-CONTROLLED, RANDOMIZED, OBSERVER-BLINDED TRIAL TO EVALUATE THE EFFICACY, SAFETY, TOLERABILITY, IMMUNOGENICITY, AND LOT CONSISTENCY OF A 6-VALENT OSPA-BASED LYME DISEASE VACCINE IN HEALTHY PARTICIPANTS ≥5 YEARS OF AGE

Acronym: VALOR

Important dates

Study start
2022
Primary completion
2026
Study completion
2026
First posted
Jul 28, 2022
Registry last updated
Jun 4, 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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