Posted: 7th April 2025
Respiratory syncytial virus (RSV) is a common infectious disease that causes infections of the lungs and respiratory tract.1 Symptoms of RSV are generally mild and mirror that of the common cold; however, the virus can cause more severe infection, including hospitalisation or death, in infants (under 12 months), older adults, or immunocompromised individuals.1 RSV is a seasonal disease, with cases generally rising in October and remaining elevated for 5 months in the UK.2 The disease places a significant burden on the population, with an estimated 24,000 hospitalisations and 11,800 deaths for adults annually in the UK.3 In particular, it has been estimated that in England, RSV accounts for 251 respiratory hospital admissions per 100,000 adults aged 75 years and over annually.4
Historically, RSV treatment and prevention options have been limited, but in the last two years both vaccines and a prophylactic monoclonal antibody have gained approval for the prevention of RSV in infants and older adults. RSV vaccines Abrysvo and Arexvy, developed by Pfizer and GSK respectively, both demonstrated efficacy in reducing lower respiratory tract infection in adults aged over 60.5, 6 Abrysvo was licensed in the UK by the Medicines and Healthcare Products Regulatory Agency (MHRA) in November 2023.7 In June 2024, the UK Joint Committee on Vaccination and Immunisation (JCVI) recommended programmes of immunisation for infants, pregnant mothers and older adults.8 The JCVI adult vaccination programme began on the 1st September 2024, offering an RSV vaccine (Abrysvo) to those aged 75 to 79 as well as those turning 75.8
This article aims to summarise the roll out of England’s RSV older adult vaccination programme, assessing vaccine uptake and the impact of vaccine availability on hospitalisations due to RSV.
Beginning in September 2024, adults in England aged 75–79 were invited to receive an RSV vaccine as part of the older adult catch up cohort. Uptake data for this cohort, reported by NHS England, are presented for the first 28 weeks of the programme (1st September 2024 to 23rd March 2025; Figure 1).9 The RSV vaccination data is sourced from the Federated Data Platform (FDP) which are based on data from different GPs and other systems. Weekly cumulative uptake was then divided by the total eligible population (2,387,125) to calculate the % vaccine uptake. The eligible population estimate was sourced from the 2023 Office for National Statistics population data.10
As of 9th March 2025, RSV vaccine uptake in the older adult cohort in England has reached 63.3% which is below the level of influenza vaccine uptake in adults aged 65 and over (Figure 1).
Abrysvo is a non-live bivalent recombinant vaccine, meaning that it contains versions of two proteins found on the surface of the virus. Interim results from an ongoing phase 3, multicentre, double-blind, randomised, placebo-controlled trial of Abrysvo in over 34,000 adults aged 60 years or older showed that the vaccine has an efficacy of 66.7% and 85.7% against RSV-associated lower respiratory tract illness with at least two and at least three signs or symptoms, respectively.6 The roll out of the vaccine to older adults is expected to reduce the number of patients admitted to hospital with RSV and modelled analyses predicted that the catch-up programme could prevent 2,000 hospital admissions in England and Wales in its first season.11
The rate of hospital admissions (excluding Intensive Care Units and High Dependency Units) is reported for England by the UK Health Security Agency (UKHSA) through SARI Watch sentinel surveillance.12 Based on this source, the weekly hospital admission rates of RSV positive cases per 100,000 population are presented for those 75 years and above for the 2023–2024 season (pre-vaccination programme) and the 2024–2025 season (post-vaccination programme; Figure 2). So far, the hospital admission rates of RSV positive cases in adults aged 75+ for the 2024–2025 season have been comparable to the 2023–2024 season, when an RSV vaccine was not available for the older adult population.
The most recent winter season saw record influenza and norovirus levels, alongside COVID-19 and RSV, which sparked fears of a potential ‘quad-demic’.13 Vaccination programmes against these viruses aim to reduce the burden of disease and pressure on the NHS. With the roll out of the RSV vaccine in England over 60% of those aged 75–79 have been vaccinated to date. However, Figure 1 demonstrates that RSV vaccine uptake in 2024–25 is reduced compared with influenza vaccine uptake for the same season in England (63.3% versus 79.9%, respectively). This could potentially be explained by a lack of awareness of the RSV vaccine programme as this is only the first season of roll out, whereas the influenza vaccine has been dosed annually for a significant period of time. In February 2025, the NHS issued invitations to around 1.3 million older people across England who have not yet had the RSV vaccine, to encourage further uptake of the vaccine.14
Based on our analysis, despite over 60% of the eligible older adult population receiving a dose of an RSV vaccine in England since September 2024, rates of hospital admissions of RSV positive cases do not appear to have decreased so far in the 2024–25 season compared to the 2023–24 season. This finding is surprising given that previous epidemiological models predicted that vaccine roll out would result in a reduction in cases and hospitalisations within the eligible elderly population.11 However, it is possible that overall RSV infection rates were higher this season than the previous, and therefore the vaccines are having a preventative effect and this season’s hospitalisation data do represent a decrease in hospitalisations compared with if no vaccine programme was launched.
As an example of epidemiological modelling research, a recent study from the UKHSA, which analysed RSV hospitalisation data in patients in England between November 2024 and January 2025, indicates that RSV vaccination has resulted in a 30% reduction in RSV hospitalisation rates among adults aged 75–79.15 One explanation for the difference in results between our analysis and the UKHSA study, is that the UKHSA study compares the hospitalisation rate for those aged 75–79 in England this season with a modelled expected hospitalisation rate for the 2024–25 season in the absence of a vaccine programme, whereas our analysis compares data from the 2024–25 season (when vaccines were available) with data from the 2023–24 season (when vaccines were not available). A further consideration for this comparison is that hospitalisation data published by the UKHSA (Figure 2) presents hospitalisation rates for individuals aged 75+, yet the UKHSA study focuses on the vaccine eligible population aged 75–79. Therefore, it is possible that hospitalisation rates have decreased for the population aged 75–79 specifically, however our data are not granular enough to detect this.
Data from Public Health Scotland supports the UKHSA study and has shown that their vaccination programme which launched in August 2024 and had an uptake of 68.6% of the eligible population by the end of November 2024, led to a 62.1% reduction in RSV-related hospitalisations among 75–79-year-olds.16 These findings align with the levels of protection observed in the clinical trial of the Abrysvo vaccine,6 and the reported real-world effectiveness against RSV hospitalisations in the United States in adults aged 60 years and older during the 2023–24 season.17 The improved protection against RSV-related hospitalisations in Scotland, compared to England, could be due to the earlier start date of their programme and the increased level of vaccine uptake in the eligible population occurring earlier in the RSV season.
While the comparison between elderly RSV hospitalisation rates in England in 2023–24 and 2024–25 showed minimal differences, epidemiological modelling studies in England and Scotland indicate that elderly RSV vaccine roll out has reduced hospitalisation rates compared with modelled hospitalisations in a non-vaccinated population. Therefore, these analyses represent some the methods of measuring the real world impact of elderly RSV vaccine roll out in England. Reduced uptake is expected in the first year of vaccine availability due to reduced awareness in both healthcare practitioners and the general population, however, a future vaccination strategy where COVID-19, influenza and RSV vaccines are offered and dosed in combination each season could further increase uptake, resulting in a greater number of illnesses, hospitalisations and deaths averted.18, 19
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If you would like any further information on the themes presented above, please get in touch, or visit our Infectious Disease Modelling page to learn how our expertise can benefit you. Tristan Curteis (UK Head of Statistics), William Bentley (Senior Analyst) and Madeline Smith (Epidemiologist) created this article on behalf of Costello Medical. The views/opinions expressed are their own and do not necessarily reflect those of Costello Medical’s clients or affiliated partners.
