RSV Vaccines Cut Hospitalizations in Older Adults but Show Gaps in High-Risk Groups
A new study evaluating respiratory syncytial virus (RSV) vaccines during their first 2 years of availability in the US demonstrates significant protection against RSV-associated hospitalization in adults aged 60 years and older. However, findings highlight lower vaccine effectiveness in immunocompromised patients and those with cardiovascular disease, underscoring the need for continued monitoring of vaccine durability and revaccination strategies.
The analysis included 6958 adults hospitalized with acute respiratory illness across 26 hospitals in 20 states between October 2023 and April 2025. Patients were eligible if they underwent respiratory virus testing within 10 days of illness onset. Case patients tested positive for RSV only, while controls tested negative for RSV, SARS-CoV-2, and influenza.
Of the total participants, 821 (11.8%) were confirmed RSV cases and 6137 (88.2%) were controls. Median age was 72 years, and just over half (50.8%) were female. A substantial proportion were immunocompromised (26.3%), and the cohort reflected racial diversity, with 20.1% Black and 62.0% White participants.
Only 15.7% of controls and 7.7% of cases had received a single RSV vaccine dose at least 14 days before illness onset. Overall, vaccination reduced the risk of hospitalization by 58% (95% CI, 45%-68%) across 2 consecutive RSV seasons. Protection was stronger when vaccination occurred in the same season as illness onset (69%; 95% CI, 52%-81%) compared with vaccination in the prior season (48%; 95% CI, 27%-63%), suggesting waning immunity over time.
Effectiveness varied significantly across clinical groups. Among immunocompetent adults, vaccine effectiveness reached 67% (95% CI, 53%-77%), while among immunocompromised adults, protection dropped sharply to 30% (95% CI, −9% to 55%). Similarly, those with cardiovascular disease experienced lower vaccine effectiveness (56%; 95% CI, 32%-72%) compared with adults without cardiovascular disease (80%; 95% CI, 62%-90%).
“Respiratory syncytial virus vaccines prevented RSV-associated hospitalization during 2 seasons, although effectiveness was lower in patients with immunocompromise and cardiovascular disease than in those without these conditions,” concluded the authors.
For pharmacists, these results carry direct relevance in guiding patient counseling and vaccine recommendations. Older adults, particularly those aged 75 years and above or adults aged 60 to 74 years with comorbidities, remain prime candidates for RSV vaccination. However, pharmacists should recognize that effectiveness may be reduced in patients with compromised immune systems or underlying cardiovascular conditions, reinforcing the need to pair vaccination with heightened vigilance and preventive measures.
The differential protection observed between same-season and prior-season vaccination raises questions about the optimal interval for revaccination. Pharmacists should anticipate future guidance from health authorities as more data emerge on the duration of immunity and the potential need for annual or periodic boosters.
Reference
Surie D, Self WH, Yuengling KA, et al. RSV vaccine effectiveness against hospitalization among US adults aged 60 years or older during 2 seasons. JAMA. 2025;30:e2515896. doi:10.1001/jama.2025.15896
