A new UK study has confirmed that vaccinating pregnant women against RSV, a major cause of serious lung infections in babies, can dramatically reduce the risk of hospitalisation for their newborns, a study published in The Lancet Child & Adolescent Health on Sunday has revealed.

RSVpreF, as the vaccine is called, was introduced across England and Scotland in late summer 2024. It is offered to all pregnant women in their third trimester, starting at 28 weeks of pregnancy.

The study found that babies whose mothers received the vaccine more than two weeks before giving birth were 72% less likely to be admitted to hospital with RSV-related lung infections.

“Maternal RSVpreF vaccination was effective and equivalent to trial settings in reducing the risk of hospitalisation in infants with RSV-associated ALRI,” the researchers wrote, referring to acute lower respiratory infections (ALRI), which are the most common form of serious RSV illness in babies.

The study found “the adjusted effectiveness of maternal RSVpreF vaccination for preventing infant hospitalisation was 58% (95% CI 28–75) for infants whose mothers were vaccinated at any time before delivery and 72% (48–85) for infants whose mothers were vaccinated more than 14 days before delivery.”

Timing matters

Researchers highlighted that not all women were able to access the vaccine in time. In a linked survey, 35% of mothers said they “disagreed or strongly disagreed with the statement ‘the RSV vaccine was easy for me to get’.

“A longer period of up to 5 weeks from RSVpreF administration to birth could provide better protection,” the study notes. “Ensuring that pregnant individuals can access RSVpreF vaccination as soon as possible… should be a priority for policy makers.”

Once hospitalised, vaccine may bot prevent severe illness.

While the vaccine helps prevent hospitalisations, it doesn’t appear to reduce the severity of illness for babies who still end up in hospital.

“Once hospitalised, outcomes for the infants of vaccinated mothers… were similar to those for infants whose mothers had not been vaccinated.”

The authors said more research is needed to understand whether the vaccine affects how long babies stay in hospital or whether they need oxygen or intensive care.

The research offers strong support for including the RSV vaccine as a routine part of pregnancy care in the UK and beyond, especially since babies under 6 months old are most at risk from RSV-related complications.

Also read: WHO recommends global rollout of RSV vaccines to save infant lives