Respiratory Syncytial Virus Vaccine Effectiveness in Medicare Beneficiaries Residing in Nursing Homes
Respiratory syncytial virus vaccination was associated with fewer serious respiratory syncytial virus outcomes in nursing home residents.
*Retrospective cohort study; Level 2 (OCEBM).
Citation
Wiegand RE, Sung HM, Zhang Y, et al. Respiratory Syncytial Virus Vaccine Effectiveness in Medicare Beneficiaries Residing in Nursing Homes. JAMA Internal Medicine. Published online August 31, 2026. doi:10.1001/jamainternmed.2026.3841
Background
Older nursing home residents have high risk for severe respiratory syncytial virus illness. This study evaluated vaccine performance during the first season these vaccines were available.
Patients
597,430 Medicare fee-for-service beneficiaries aged 65 years or older living in United States nursing homes. Exclusions included prior recent respiratory syncytial virus, hospice care, dialysis encounters, prior clot-related events, incomplete Medicare enrollment, or invalid vaccine records.
Intervention
One respiratory syncytial virus vaccine dose, either Arexvy or Abrysvo.
Control
No recorded respiratory syncytial virus vaccination.
Outcome
Respiratory syncytial virus–associated hospitalization, death, severe outcome, and clot-related event, identified through Medicare claims.
Follow-up Period
October 1, 2023, to March 30, 2024.
Results
| Outcome | Vaccine effectiveness | Approximate crude NNT |
|---|---|---|
| Hospitalization (primary) | 73% (95% CI 65% to 79%) | 263 |
| Death | 56% (95% CI 39% to 69%) | 805 |
| Severe outcome | 59% (95% CI 44% to 70%) | 601 |
| Clot-related event | 66% (95% CI 44% to 79%) | 1190 |
CI = confidence interval; NNT = number needed to vaccinate, estimated from unadjusted seasonal event risks.
Effectiveness was similar for both vaccine products. Protection against hospitalization was 75% in residents aged 75 years or older and 61% in immunocompromised residents.
Limitations
Observational claims data cannot prove causation. Vaccine status, diagnoses, and outcomes may have been misclassified. Unmeasured differences, such as health-seeking behavior or advance care plans, may have biased results. Findings apply best to Medicare fee-for-service nursing home residents.
Funding
CDC/CMS funded; one author reported Sanofi and Merck stock.
Clinical Application
Offer respiratory syncytial virus vaccination to eligible nursing home residents; this evidence supports current recommendations for high-risk older adults.
Discussion
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In this retrospective cohort study, RSV vaccination was associated with lower RSV-associated hospitalization in nursing home residents (VE 73%, 95% CI 65%-79%); given the nonrandomized design, should these findings change vaccination practice, and what validity or applicability concerns remain? The authors reported RSV vaccine effectiveness of 73% against RSV-associated hospitalization, calculated as (1 − hazard ratio) × 100%. Which interpretation is most appropriate?