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.

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.