By FieldPulse Editorial · March 24, 2026
Tags: Clinical Trials, FDA, Pipeline
The Pfizer-Valneva Lyme disease vaccine showed more than 73% efficacy in a Phase 3 trial but missed its predetermined statistical threshold, leaving the regulatory path uncertain for what would have been the first Lyme vaccine approved in over two decades.
A Phase 3 trial of the Pfizer-Valneva Lyme disease vaccine has produced a result that is at once encouraging and commercially disappointing: the vaccine demonstrated efficacy above 73%, but failed to cross the predetermined statistical confidence interval required to meet the trial's primary endpoint. Pfizer said it plans to discuss the results and potential regulatory options with the FDA. The company has not ruled out a path to approval, but the missed primary endpoint introduces meaningful uncertainty into a program that had generated significant interest — Lyme disease affects hundreds of