Three recent UK studies offer complementary insights into maternal respiratory syncytial virus (RSV) vaccination, with real-world data supporting protection against infant RSV hospitalisation up to six months of age and maternal perspectives highlighting the importance of access, information and vaccine confidence. Here, Andrea Porter explores the results.

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infection and hospital admission in infants. In 2024, the UK introduced a national maternal vaccination programme, with a bivalent RSV prefusion F (RSVpreF) vaccine (brand name Abrysvo) offered from 28 weeks’ gestation.

Since this rollout, various groups of UK researchers have investigated the implementation, delivery and effectiveness of maternal RSV vaccination, as well as the response to it, and three such studies are discussed here.

A qualitative study considered views of maternal RSV vaccination and preferences for vaccine delivery, and two studies from the UK BronchStop programme examined maternal experiences during the first season, and real-world vaccine effectiveness during the second season, respectively.

RSV vaccine perceptions and information preferences

The qualitative study published in the journal Vaccine provides perspectives on how maternal RSV vaccination might be delivered, by considering maternal views of RSV vaccination and their preferences for information and vaccine delivery.

The researchers explored RSV awareness, vaccine perceptions and preferences among 30 mothers in England who were recruited following a UK Health Security Agency survey. Semi-structured interviews were conducted between July and November 2024 and analysed thematically.

Most participants had heard of RSV, although understanding varied considerably. Social media, particularly TikTok and Instagram, had helped to raise awareness through parents sharing experiences of severe RSV in children. Notably, however, social media was not regarded as a trusted source of maternal vaccine information.

After being shown NHS information on maternal RSV vaccination, most women expressed positive views on accepting it in a current or future pregnancy. Protecting their baby was an important motivation, although some wanted more information on safety, side effects and the duration of protection before deciding.

Participants favoured receiving information earlier in pregnancy, giving them time to consider vaccination and ask questions before making an informed decision. Most preferred a combination of online and written NHS information alongside opportunities to discuss vaccination with a midwife.

Convenience was also considered important. Most participants favoured receiving maternal vaccines in maternity settings as part of existing antenatal appointments rather than arranging a separate general practice visit.

Limitations and conclusions

The small study had important limitations. Only two participants were pregnant at the time of interview, meaning most were hypothetically considering RSV vaccination. In addition, only two participants reported that they were unlikely to accept it, limiting the exploration of reasons for non-acceptance.

The authors also noted that participants may have held more favourable views towards vaccination than the wider population, socioeconomic status and education were not collected, and several participants had health-related backgrounds, which was likely to have influenced their vaccine perceptions and awareness.

Nevertheless, they concluded that the findings highlighted key factors shaping maternal RSV awareness, vaccine perceptions and acceptability, alongside practical considerations for optimising maternal vaccine communication and delivery.

Barriers to RSV vaccine uptake identified

Published in the Archives of Disease in Childhood, another study examined free-text survey responses collected during the national RSV programme’s first season. The survey questionnaire was designed to explore factors influencing uptake of RSVpreF, addressing confidence, complacency, constraints, calculation (risk assessment) and collective responsibility.

The respondents comprised 388 vaccine-eligible mothers whose infants had been hospitalised with bronchiolitis, lower respiratory tract infection or acute wheeze at 30 hospitals across England and Scotland.

Of these mothers, 82 had received RSVpreF, 299 had not, and vaccination status was unknown for seven.

Four principal themes emerged during the analysis: access-related barriers, insufficient awareness and information, vaccine safety concerns and hesitancy, and perceptions of vaccination as beneficial and protective.

Access was the most commonly reported barrier, cited by 210 mothers (54%). Some 102 (26%) said vaccination had not been offered, or they could not recall being offered it, and a third of these women said they would have accepted vaccination if given the opportunity.

A further 53 (14%) reported being offered vaccination too late in pregnancy, or after giving birth, while 47 (12%) described logistical difficulties such as inconvenient vaccination locations, limited appointments, staffing pressures, stock shortages and unclear booking arrangements.

Information was another prominent concern, with 112 mothers (29%) reporting insufficient information about the vaccine or the risks of RSV and 38 (10%) raised concerns about vaccine safety or its recent introduction.

The mothers emphasised the value of clear, consistent information to support informed choices and that healthcare professionals could influence decisions positively or negatively.

Conversely, 52 participants described vaccination as an important means of protecting their baby, with previous personal or professional experience of RSV or serious respiratory illness among the factors motivating vaccination.

Limitations and conclusions

These findings require careful interpretation as the authors noted that participants were mothers of infants already hospitalised with respiratory illness and their perspectives may therefore differ from the wider population.

Geographical differences in consent rates may also have introduced selection bias, while surveys conducted by healthcare professionals could have influenced responses.

The authors concluded that enhancing maternal RSV vaccine uptake requires systemic barriers to access being addressed and the integration of RSV education into routine antenatal care.

They also highlighted the importance of healthcare professionals providing clear, evidence-based information to support informed decision-making and equal access to RSV vaccine benefits.

Maternal RSV vaccination and infant hospitalisation risk

A prospective, test-negative case-control study, published in The Lancet Child & Adolescent Health, was conducted at 37 UK hospitals during the 2025/26 RSV season.

It enrolled infants aged six months or younger who were admitted with acute lower respiratory tract infection and underwent RSV testing. The primary analysis included 429 RSV-positive and 265 RSV-negative infants born at 28 weeks’ gestation or later who had not received nirsevimab.

The mothers of 161 (38%) RSV-positive infants had received RSVpreF before delivery, compared with 175 (66%) of RSV-negative infants.

After adjustment for geographical site, month of admission, gestational age, socioeconomic status, infant age and breastfeeding, the estimated vaccine effectiveness against hospital admission with RSV-associated acute lower respiratory tract infection through to six months of age was 61% (95% CI 38–75%). Estimated effectiveness was higher through to three months of age, at 76% (95% CI 54–87%).

Unadjusted analyses across two-month age bands also suggested decreasing protection with increasing infant age, although confidence intervals were wide.

‘Greatly reduced risk of babies being admitted’

Commenting on the findings, study coordinator Dr Shaun O’Hagan, paediatric infectious diseases doctor and PhD student at Queen’s University Belfast, said: ‘We found that vaccination during pregnancy greatly reduced the risk of babies being admitted to hospital with RSV-related respiratory illness.

‘Put simply, for every four babies who might otherwise have needed hospital care for RSV, three avoided admission because their mother was vaccinated against the virus in pregnancy.’

Dr O’Hagan also emphasised that population-level protection depends on uptake, noting that around 63% of eligible pregnancies in England currently receive the RSV vaccine, compared with around 90% infant immunisation coverage in countries such as Spain.

Timing of vaccination differed substantially from the first season of the programme. Median gestational age at vaccination was 30 weeks in the second season compared with 35 weeks previously.

Unlike the team’s first-season analysis, excluding infants born within 14 days of vaccination did not change the estimated effectiveness, which remained at 61% (95% CI 39–76%). The authors suggested this probably reflected earlier vaccination during the second season, meaning fewer infants were born shortly after maternal immunisation.

The analysis was then broadened to assess the overall UK infant RSV prevention programme, which includes single-injection nirsevimab for premature babies.

When infants born at any gestation, and those protected through maternal RSVpreF, nirsevimab or both, were included, the estimated programme effectiveness against RSV-associated acute lower respiratory tract infection hospitalisation through to six months was also 61% (95% CI 39–75%).

However, the authors noted that relatively few recruited infants had received nirsevimab, and population-level impact data were unavailable.

Limitations and conclusions

What’s more, the observational test-negative design leaves room for residual confounding and other biases. The study also could not assess protection beyond six months or against intensive care admission, and subgroup analyses were considered exploratory.

The authors concluded that the UK’s infant RSV prevention programme and RSVpreF vaccination was effective up until the age of six months in reducing the risk of hospital admission with RSV-associated acute lower respiratory tract infection in the real-world setting.

Conclusion

Taken together, these three studies provide a broader picture of the UK maternal RSV vaccination programme.

Qualitative and other findings suggest that access, timely and trusted information, opportunities to discuss concerns and convenient integration into antenatal care could all be important in supporting vaccine uptake.

The effectiveness data, meanwhile, support an association between maternal RSVpreF vaccination and substantially lower odds of RSV-associated acute lower respiratory tract infection hospitalisation during the first six months of life.

References