Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants

This Original Article from a multicountry, phase 3, double-blind, placebo-controlled trial (MATISSE Study Group) evaluated the efficacy and safety of a bivalent RSV prefusion F protein-based (RSVpreF) vaccine administered during pregnancy to prevent RSV-associated lower respiratory tract illness in infants. A total of 7392 pregnant women (24–36 weeks gestation) were randomized 1:1 across 18 countries. Among infants followed for up to 180 days after birth, the vaccine showed significant efficacy against severe RSV illness (81.8%; 99.5% CI, 40.6–96.3) and RSV-associated hospitalization (67.7%; 99.17% CI, 15.9–89.5). The vaccine also showed moderate protection against medically attended RSV illness (51.3%; 97.58% CI, 29.4–66.8). No significant efficacy was observed for preventing RSV of any cause. Safety profiles in both maternal and infant populations were similar to placebo, with no safety signals detected. The study supports RSVpreF as a maternal immunization strategy to protect infants during the highest-risk period for RSV-associated severe illness.

This Original Article from a multicountry, phase 3, double-blind, placebo-controlled trial (MATISSE Study Group) evaluated the efficacy and safety of a bivalent RSV prefusion F protein-based (RSVpreF) vaccine administered during pregnancy to prevent RSV-associated lower respiratory tract illness in infants. A total of 7392 pregnant women (24–36 weeks gestation) were randomized 1:1 across 18 countries. Among infants followed for up to 180 days after birth, the vaccine showed significant efficacy against severe RSV illness (81.8%; 99.5% CI, 40.6–96.3) and RSV-associated hospitalization (67.7%; 99.17% CI, 15.9–89.5). The vaccine also showed moderate protection against medically attended RSV illness (51.3%; 97.58% CI, 29.4–66.8). No significant efficacy was observed for preventing RSV of any cause. Safety profiles in both maternal and infant populations were similar to placebo, with no safety signals detected. The study supports RSVpreF as a maternal immunization strategy to protect infants during the highest-risk period for RSV-associated severe illness.