Mothers welcome vaccine to protect unborn babies from RSV bronchiolitis

An estimated 1.4 million infants globally aged up to six-months-old require urgent hospital treatments every year after developing a condition called respiratory syncytial virus (RSV) brochiolitis. RSV bronchiolitis is the leading cause of lower respiratory infections in babies. RSV is highly contagious, and bronchiolitis causes symptoms like cough, and difficulties breathing and feeding.

In late summer 2024 the United Kingdom introduced maternal vaccination against RSV. The vaccine generates maternal immunity that is then transferred to the unborn baby, and protects them from RSV bronchiolitis after birth. The BronchStop study, lead by Thomas Williams and Steve Cunningham at the Institute for Regeneration and Repair (IRR) at the University of Edinburgh, conducted a survey of mothers whose infants had been admitted with bronchiolitis across England and Scotland. 

Over three quarters (86 per cent) of vaccinated mothers surveyed believed the new maternal bivalent RSV vaccine was necessary, and 76% believed it was safe. However, whilst the  majority of unvaccinated mothers (73 per cent) also agreed it was necessary, only just under half (49 per cent) felt confident that it was safe; and 44% stated that they were unsure about its safety.

The majority of vaccinated mothers-to-be (81 per cent) said they found it easy get access to the RSV vaccine. However, the study found over a quarter (35 per cent) of unvaccinated mothers said they found it hard to get access to the RSV vaccine, suggesting that vaccine availability, not just vaccine hesitancy, was a factor in some mothers not accessing the new RSV vaccine. 

Dr Thomas Williams, a paediatrician whose research is based at the IRR, and who co-led the study, said: "RSV causes a significant burden of disease in infants in the United Kingdom, and globally an estimated 50,000 deaths in infants under the age of 6 months. High uptake of this new maternal vaccination could make a real impact. Our study offers insights as to why some expectant mothers choose to take up the vaccine, while others did not. This is important because it help us understand why this happens, so that we can help reach expectant mums and ensure they are offered this vaccine to make informed choices, to ensure more babies are protected." 

A total of 444 mothers were recruited to the BronchStop vaccine effectiveness study in Autumn/Winter 2024 across 31 hospitals - 27 in England and four in Scotland.   Of these mothers, 421 (95%) recalled whether they had received the RSV vaccination during pregnancy.  And 88 (21%) of 421 stated that they had received the vaccine and 333 (79%) stated that they had not. 

The findings from BronchStop Study have been published in The Lancet – Infection Diseases. 

The project was funded by the Respiratory Syncytial Virus Consortium in Europe (RESCEU), the Wellcome Trust and National Institute for Health and Care Research (NIHR) Health Protection Research Unit in Respiratory Infections, Imperial College London.

The paper in The Lancet

Cunningham research group