Maternal RSV Vaccine Cuts Infant Hospitalizations by About 70%

Overview

• The peer-reviewed study published June 5, 2026, found that a single dose of the maternal RSVpreF vaccine given in pregnancy was associated with about 68% effectiveness against RSV-related hospitalization and 69% effectiveness against severe lower respiratory disease in infants under 90 days.
• Researchers analyzed hospital records from western Pennsylvania for the 2023–24 and 2024–25 RSV seasons and compared infants whose mothers received the vaccine with those who did not.
• Infants who received postnatal monoclonal antibody prophylaxis were excluded so the results reflect protection from maternal antibodies passed before birth rather than antibody given after delivery.
• The study was funded in part by Pfizer and authors reported grant support and other ties to vaccine makers, details the paper discloses to help readers weigh potential conflicts of interest.
• These are interim results from a planned four-year study; investigators will continue follow-up through additional RSV seasons and expand analysis to infants up to 180 days to measure how long maternal protection lasts and to inform clinicians and policy decisions.