Landmark study confirms RSV vaccine effectiveness in infants
The largest real-world study of maternal respiratory syncytial virus vaccination has found that the vaccine cuts infant hospitalization risk by more than 80% when given at least two weeks before birth. The research, conducted by the UK Health Security Agency and presented at ESCMID Global 2026 in Munich, analyzed data from thousands of mother-infant pairs across the United Kingdom.
Lead author Matt Wilson, a UKHSA epidemiologist, said the findings provide "robust evidence that vaccination offers substantial protection against severe illness in young infants." RSV is a leading cause of hospitalization in babies under six months old worldwide, causing bronchiolitis and pneumonia. Until recently, no vaccine was available to protect newborns, who are too young to receive most vaccinations directly.
Vaccine timing is key to protection
The study showed that the protective effect was strongest when the vaccine was administered at least two weeks before delivery. Researchers matched 354 infants hospitalized with RSV-related lower respiratory tract infections against 3,511 control infants. After adjusting for factors including infant sex, birthweight, maternal age, ethnicity, and socioeconomic status, maternal vaccination was associated with an 82.2% reduction in hospitalization risk.
The RSVpreF vaccine, which targets the pre-fusion form of the virus's F protein, has been recommended for pregnant women in several countries. The consistency of results across different studies, researchers noted, presents "a compelling public health opportunity to improve early-life outcomes."
Public health implications are substantial
RSV causes an estimated 33 million cases and up to 100,000 deaths in children under five globally each year. The finding that maternal vaccination can reduce hospitalizations by over 80% could transform pediatric care, particularly in low-resource settings where access to intensive care for infants with severe RSV is limited. Several countries are now considering expanding maternal RSV vaccination programs based on these results.