Objective: To evaluate descriptive efficacy data, exploratory immunogenicity data, and safety follow-up through study completion from the global, phase 3 MATISSE (Maternal Immunization Study for Safety and Efficacy) maternal vaccination trial of bivalent respiratory syncytial virus (RSV) prefusion F protein vaccine (RSVpreF).

Methods: MATISSE was a phase 3, randomized, double-blinded, placebo-controlled trial. Healthy pregnant participants aged 49 years or younger at 24-36 weeks of gestation were randomized (1:1) to receive a single RSVpreF 120 micrograms or placebo dose. Primary efficacy endpoints included newborn and infant severe RSV-associated medically attended lower respiratory tract illness within 180 days after birth. The RSV-A and RSV-B serum neutralizing antibody titers were determined in a subset of pregnant participants and their newborns.

Epub 2025 Jan 2.