Maternal RSV vaccine shields babies but global uptake lags far behind

Maternal vaccination against respiratory syncytial virus, the leading cause of hospitalisation among young infants worldwide, reduces the risk of severe disease in babies by around 74 per cent, according to a major new review of real-world evidence. Yet despite this striking level of protection, the same analysis reveals that uptake of the vaccine during pregnancy remains disappointingly low in many countries, with coverage varying dramatically both between nations and between communities within them. The findings, published in The Lancet Regional Health – Europe, arrive at a critical moment, as more than 30 countries have now introduced maternal RSV immunisation either as a stand-alone programme or alongside other preventive measures such as infant antibody treatment.

The review was led by a collaboration between the University of Edinburgh and the University of Granada in Spain, with contributions from Public Health Scotland, the Pan-American Health Organization, and colleagues at six other UK-based universities. The research team pooled data from 16 studies covering more than four million pregnancies between 2023 and 2025, making it one of the most comprehensive assessments to date of how maternal RSV vaccination programmes are performing outside the controlled conditions of clinical trials. By synthesising evidence from these early national rollouts, the authors sought to estimate not only how many pregnant women are receiving the vaccine, but also how well it is working and how safe it is in routine practice.

The technical case for maternal RSV vaccination rests on a straightforward biological principle. When a pregnant woman is vaccinated, her immune system generates antibodies against the virus, and these antibodies cross the placenta to reach the developing fetus. This process, known as passive immunisation, means that babies are born already carrying protective antibodies against RSV, shielding them from the moment of birth through the most vulnerable months of infancy, when their own immune systems are still immature and their airways are small enough to be dangerously compromised by infection. The new review confirms that this approach translates effectively from trials into the real world, with the vaccine reducing the risk of RSV-related hospitalisation in babies under six months by approximately 74 per cent.

Dr Ting Shi, of the University of Edinburgh’s Usher Institute, said the real-world performance matched expectations from the original clinical trials. “We found the vaccine reduced the risk of RSV-related hospitalisation in babies under six months by around 74 per cent, which lines up well with what the clinical trials predicted, and we found no evidence of an increased risk of preterm birth,” he said. “But uptake during the first vaccination seasons was low. Timing matters too. The vaccine works best when it’s given at least two weeks before birth, so making sure women can access it early in their eligibility window is key.”

The safety findings carry particular weight for a vaccine administered during pregnancy, a context in which even rumours of harm can rapidly undermine confidence. Drawing on data from more than 16,000 pregnancies, the review found no evidence of an increased risk of preterm birth among women vaccinated between 32 and 35 weeks of gestation, the window in which the vaccine is typically offered. This population-level evidence, gathered across multiple health systems and countries, provides reassurance that complements the trial data and offers policymakers a firmer foundation on which to build and defend national immunisation programmes.

The uptake figures, however, tell a more troubling story. Since the maternal RSV vaccine was introduced in the United Kingdom in September 2024, Scotland recorded its highest coverage in October 2025, when 62 per cent of pregnant women had been vaccinated, while England reached a peak of 58 per cent in August 2025. The United States, by contrast, recorded some of the lowest overall uptake, with an estimated 27 per cent of pregnant women vaccinated during the first year the maternal RSV vaccine was available there, where it is delivered alongside other preventive interventions. The researchers note that these figures fall below those achieved by other maternal vaccines, such as the whooping cough vaccine, over the same period, suggesting that RSV immunisation has yet to become embedded in routine antenatal care in the way that longer-established maternal vaccines have.

Beneath the headline national averages, the review uncovered persistent and concerning disparities. Evidence indicates lower uptake of the RSV vaccine among some socioeconomic and ethnic groups, among women with reduced access to healthcare, and among younger mothers. These patterns echo long-standing inequities in maternal immunisation more broadly, in which the families who face the highest burdens of infectious disease are often the least likely to receive preventive care. Dr Kimberly Marsh, Viral Respiratory Pathogens lead at Public Health Scotland, said the review demonstrates that protection is not being distributed equally. “This review shows that maternal RSV vaccination is protecting babies from severe illness but uptake is not equal across all communities,” she said. “Monitoring vaccine coverage and addressing barriers faced by some ethnic groups and more deprived communities will be important to ensure that all families can benefit from protection the RSV vaccine offers to babies.”

The implications of these disparities extend beyond individual health outcomes. RSV places a substantial seasonal burden on paediatric intensive care units every winter, and the effectiveness of a vaccination programme in reducing that burden depends on achieving sufficiently high and evenly distributed coverage. If uptake remains concentrated among more affluent, better-served populations, the public health dividend of the vaccine will be blunted, and the communities already experiencing the worst outcomes from RSV infection will continue to bear a disproportionate share of the disease. The review’s authors argue that targeted outreach, improved supply chain systems, and robust immunisation policies are needed as RSV vaccination programmes are rolled out globally, so that the benefits of the intervention reach the full population of newborns rather than a privileged subset.

Dr Evelyn Balsells of the University of Granada emphasised that the scientific evidence is now firmly established and that the remaining challenge is one of implementation and equity. “Research shows that RSV vaccination during pregnancy protects babies,” she said. “Efforts to increase uptake and reduce disparities will be essential to maximise the benefits of maternal RSV vaccination.” Her point underscores a familiar trajectory in vaccinology: the development of a safe and effective product is only the first step, and the harder work of building delivery systems, public trust, and equitable access often determines whether a vaccine fulfils its potential at the population level.

As additional countries introduce RSV prevention programmes in the coming seasons, the authors argue that continued analysis of emerging real-world evidence will be essential. Systematic monitoring of vaccine coverage, effectiveness, and safety allows health authorities to track the impact of immunisation, support policymakers and healthcare workers in their decision-making, and inform pregnant individuals about the choices available to them. The first two years of maternal RSV vaccination have demonstrated that the science works: the vaccine is effective, the safety signal is reassuring, and the protection it confers on newborns is substantial. The task now facing health systems around the world is to close the gap between what the vaccine can achieve and what it is actually delivering, ensuring that every baby who could benefit from protection against one of childhood’s most common and dangerous viruses has the chance to receive it.

Subject of Research: Real-world uptake, effectiveness and safety of maternal RSV vaccination worldwide

Article Title: Global study finds stark differences in RSV vaccine uptake

Article References: Global study finds stark differences in RSV vaccine uptake. (n.d.). Original publication

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Keywords: RSV, maternal vaccination, vaccine uptake, systematic review, infant health, public health, vaccine safety, health equity, University of Edinburgh, The Lancet Regional Health – Europe, respiratory syncytial virus, pregnancy