Maternal RSV Vaccination Reduces Infant Hospitalization by Over 80%

A major real-world study conducted in England has confirmed that maternal respiratory syncytial virus (RSV) vaccination provides over 80% protection against infant hospitalization, reinforcing the vaccine’s critical role in safeguarding newborns during their most vulnerable early months.

The UK Health Security Agency (UKHSA) analyzed data from nearly 300,000 babies born between September 2024 and March 2025, covering approximately 90% of all births in England during that period. The study evaluated the effectiveness of the maternal RSV vaccination programme, which is offered to women from 28 weeks of pregnancy.

Infants whose mothers received the RSV vaccine at least two weeks before birth had an 81.3% reduced risk of hospitalization due to RSV infection. The statistical uncertainty around this figure ranged from 78.9% to 83.4%, indicating high confidence in the vaccine’s protective effect.

Protection was even higher for babies born at least four weeks after maternal vaccination, with nearly 85% reduction in hospital admissions. These findings underscore the importance of timely vaccination, ideally administered in week 28 of pregnancy or shortly thereafter, to maximize antibody transfer to the fetus.

More than 4,500 hospitalizations for RSV-related chest infections, including bronchiolitis, occurred in the cohort. The vast majority of these cases involved infants whose mothers had not been vaccinated, highlighting the preventable burden of severe RSV disease in early infancy.

The study is described as the largest real-world evaluation of maternal RSV vaccination to date, offering robust evidence on the programme’s impact in a national healthcare setting. It supports earlier clinical trial data showing over 80% efficacy of the RSVpreF vaccine in preventing severe infant respiratory illness.

RSV remains a leading cause of hospital admission in infants worldwide, particularly during seasonal outbreaks. By vaccinating pregnant individuals, public health authorities aim to provide passive immunity to newborns who are too young to receive vaccines directly.

Health officials continue to emphasize the safety and effectiveness of maternal RSV vaccination as a key strategy to reduce infant morbidity and healthcare strain during peak RSV seasons. Ongoing monitoring will assess long-term impact and inform future immunization policies.