Pfizer and Valneva will evaluate a 6-valent OspA-based Lyme disease vaccine (VLA15) for the prevention of Lyme disease within North America and Europe in a phase 3 clinical trial. 

Approximately 6,000 healthy participants 5 years and older will be recruited from areas with high levels of endemic Lyme disease to receive VLA15 or a 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 a 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 later.