A systematic review indicates that vaccinating pregnant women with Pfizer’s Abrysvo can cut severe RSV illness in infants by up to 84%, offering promising safety data and supporting current immunisation guidelines amidst calls for broader global research.
A new systematic review suggests that vaccinating during pregnancy can substantially reduce the risk of serious RSV illness in babies during the first months of life, offering one of the clearest indications yet that maternal immunisation can help blunt a virus that has long filled paediatric wards each winter. The review, published in New Microbes and New Infections, found that the authorised prefusion F vaccine, sold by Pfizer as Abrysvo, lowered medically attended RSV illness, severe lower respiratory tract disease and hospitalisation in infants, while showing no major safety signal in mothers or babies.
That matters because RSV remains a major cause of infant illness worldwide. In 2019, the virus was linked to millions of lower respiratory infections in young children and a large share of deaths in babies younger than six months, according to the review. For clinicians and parents alike, that early window is crucial: newborns have small airways, immature immune systems and limited ability to mount their own defence. The strategy behind maternal vaccination is straightforward. Antibodies generated in pregnancy cross the placenta and give the infant temporary protection at the point when the risk is highest.
The updated review drew on randomised trials and real-world studies published through June 2025. In the pooled trial data, maternal vaccination cut medically attended RSV lower respiratory tract infection by 68% in the first 90 days after birth and reduced severe disease by 84%. A large trial also showed a 70% drop in RSV-related hospitalisation. The authors said the evidence for those outcomes was high certainty, meaning they had strong confidence the true effects were close to the estimates seen in the studies.
Safety findings were broadly reassuring. The review found no clear difference in infant death, intensive care admission or other rare serious outcomes, although those measures were too uncommon for precise estimates. It also found no signal for preterm birth with the licensed vaccine. A separate review indexed by PubMed reported similar conclusions, finding no significant differences in congenital abnormalities, stillbirth, intrauterine growth restriction or infant death. The main side effects were typical vaccine reactions such as soreness, swelling, redness, fatigue and headache.
The findings also fit with current U.S. guidance. The Centers for Disease Control and Prevention recommends maternal RSV vaccination as one option for infant protection, alongside long-acting infant antibodies such as nirsevimab and clesrovimab, and says most babies will not need both. The new review supports that approach, while also calling for longer follow-up, broader surveillance and more data from low- and middle-income countries, where RSV deaths are concentrated. For now, the message is that maternal RSV vaccination appears to offer meaningful early protection for infants, with a safety profile that is, on current evidence, reassuring.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
