For the first time since LYMErix was pulled from the U.S. market in 2002, a Lyme disease vaccine is on the verge of regulatory approval — and the Phase 3 trial results suggest it is substantially effective in both adults and children as young as 5 years old. Pfizer and Valneva announced on March 23, 2026 that their investigational 6-valent OspA-based Lyme disease vaccine candidate, PF-07307405 (LB6V, formerly known as VLA15), demonstrated efficacy of 73.2 to 74.8 percent in preventing confirmed Lyme disease cases in the Phase 3 VALOR (Vaccine Against Lyme for Outdoor Recreationists) clinical trial.
The announcement came at the end of a two-year trial conducted across sites in highly endemic areas of the United States, Canada, and Europe — the precise regions where 500,000 Americans are estimated to contract Lyme disease every year. The trial enrolled participants aged 5 and older and randomized them to receive four doses of either the vaccine or a saline placebo, given one dose each at months 0, 2, 5 to 9, and a booster one year after the third dose.
