Valneva and Pfizer declare positive data of Lyme disease vaccine booster's trial

Valneva and Pfizer have announced positive results from the Phase II VLA15-221 trial, which tested a second booster dose of their Lyme disease vaccine candidate, VLA15, administered a year after the initial booster. VLA15 is an experimental multivalent protein subunit vaccine that targets outer surface protein A (OspA) of Borrelia burgdorferi, the bacterium causing Lyme disease.

The study, a randomized, observer-blind, placebo-controlled trial, involved 560 healthy pediatric participants aged 5 to 17. Each received a 180µg dose of the vaccine or a placebo, with boosters given at 18 and 30 months. Results showed similar immune responses and safety profiles after the second booster compared to the first, with antibody responses exceeding 90% across all six OspA serotypes.

Pfizer aims to file a Biologics License Application (BLA) with the FDA and a Marketing Authorisation Application (MAA) with the EMA in 2026, contingent on successful Phase III outcomes.