Safety and immunogenicity of a virus-like particle pandemic influenza A (H1N1) 2009 vaccine in a blinded, randomized, placebo-controlled trial of adults in Mexico

► The safety and immunogenicity of one or two doses of a recombinant A (H1N1) 2009 influenza VLP vaccine was evaluated in a two-stage, Phase 2, randomized, double-blind, placebo-controlled study conducted during the H1N1 2009 pandemic in Mexico. ► The H1N1 2009 VLP vaccine was safe and well-tolerated with no vaccine-related serious adverse events. ► The VLP vaccine groups demonstrated robust HAI immune responses after a single vaccination, which were statistically higher compared to placebo.