Vimkunya: The Second Chikungunya Vaccine to Be Licensed in the U.S.

The mosquito-borne chikungunya virus (CHIKV) causes periodic outbreaks in tropical and subtropical regions. While mortality is low at 0.35%, acute disease can cause incapacitating chronic joint pain. In a phase 3 U.S. trial of the CHIKV virus-like particle vaccine (Vimkunya), Richardson and colleagues randomized 3258 teens and adults (73% white; 98% CHIKV-seronegative) to receive a single dose from one of three vaccine lots or placebo. They assessed the differences among groups in CHIKV seroresponses and geometric mean titers (GMTs) of anti-CHIKV neutralizing antibodies (nAb); pairwise nAb GMT ratios were also calculated among recipients of vaccine from each lot.

At day 22 in the Vimkunya and placebo groups, seroresponses were 98% and 1%, re…