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.
Age range
18 Years – 44 Years
Sex
ALL
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Geometric Mean Concentration (GMC) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG)
Timeframe: At 1 month after the fourth VLA15 dose
Geometric Mean Fold Rise (GMFR) of Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations
Timeframe: Before the first dose to 1 month after the fourth VLA15 dose
Sero-Response Rate Based on Anti-Outer Surface Protein A (OspA) Immunoglobulin G (IgG) Concentrations.
Timeframe: Before the first dose to 1 month after the fourth VLA15 dose
Percentage of Participants With Local Reactions For Each Group
Timeframe: Within 7 days after each vaccination
Percentage of Participants With Systemic Events For Each Group
Timeframe: Within 7 days after each vaccination
Percentage of Participants With Adverse Events (AEs) For Each Group
Timeframe: Within 1 month after each vaccination
Percentage of Participants With Serious Adverse Events (SAEs) For Each Group
Timeframe: From the time the participant provides informed consent up to approximately 6 months after the last vaccination
Percentage of Participants With Newly Diagnosed Chronic Medical Conditions (NDCMCs) For Each Group
Timeframe: From the time the participant provides informed consent up to approximately 6 months after the last vaccination