Study Finds Reduction in RSV Hospitalizations Among Vaccinated Older Adults in England

A mid-season analysis published by investigators in The Lancet reveals a significant impact of vaccination in reducing hospital admissions linked to respiratory syncytial virus (RSV), underscoring the importance of RSV immunization for older adults.¹

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RSV can cause severe outcomes for high-risk individuals, including those aged 75 years and older and those with chronic or underlying health conditions. Individuals infected with severe RSV typically present mild cold-like symptoms; however, in some cases hospitalization is needed. Additionally, RSV could worsen serious conditions, including asthma, chronic obstructive pulmonary disease, and heart failure, according to the CDC.²

Currently, the CDC recommends an RSV vaccine to all individuals aged 75 years and older and individuals aged 60 to 74 years that are at increased risk for severe RSV.²

In the 2023-2024 season in the US, a population-based study of healthy adults aged 60 years and older demonstrated 80% protection against RSV-related hospitalizations due to vaccination. Based on this type of evidence, the UK initially recommended RSV vaccination in England for individuals aged 75 years, with a catch-up to age 79, while awaiting more data on older individuals. Following, in September 2024, individuals residing in England aged 75 to 79 years were administered a single dose of Pfizer’s bivalent prefusion F Abrysvo vaccine, according to study authors.¹

To assess the impact of vaccination on RSV-related hospitalization in older adults, researchers conducted a regression discontinuity design study, including patients aged 70 to 84 years with a positive RSV test between 14 days before and 2 days after hospital admission.¹

When the vaccination period began, a total of 2,541,696 individuals aged 75 to 79 were eligible for the Abrysvo vaccine. By the study’s start on November 4, 2024, the overall vaccine coverage was 35.1%, with 830,260 doses administered. This coverage increased to 47.4% by the study’s conclusion on January 6, 2025, with 1,183,817 doses given. By the end of the study period, vaccine coverage ranged from 45.0% in individuals aged 75 years to 48.9% in individuals aged 79 years, according to study authors.¹

The results demonstrated a drop in hospitalization rates that were linked to a 30% reduction (95% CI 18–40, p < .0001) observed in individuals aged 75 to 79 years that were eligible for RSV vaccination. At the midpoint of the study, vaccine coverage in the eligible population was approximately 41.8%. While not designed as an effectiveness study, the authors noted the observed 30% reduction in hospitalization aligns with an expected vaccine effectiveness of 72%.¹

However, the observed 30% reduction in hospitalizations could be influenced by underlying health conditions; although, the study authors noted that because the vaccination program targeted individuals within the specific age range, differences in uptake across these risk factors are unlikely.¹

The findings suggest a positive impact of RSV vaccination on RSV-associated hospital admission, emphasizing the importance of protection, especially among older adults.¹

While future research will include end-of-season evaluations and adjusted test-negative case-control studies to refine estimates of real-world vaccine effectiveness in England, this interim assessment offers crucial evidence of RSV vaccine protection.¹

REFERENCES

1. Early impact of RSV vaccination in older adults in England. The Lancet. News release. April 5, 2025. Accessed April 11, 2025. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(25)00346-0/fulltext

2. RSV in Older Adults. CDC. News release. August 30, 2024. Accessed April 11, 2025. https://www.cdc.gov/rsv/older-adults/index.html.