Burden of Respiratory Syncytial Virus (RSV) on Severe Acute Respiratory Infection and Projected Cost Offsets of Implementing a Regional Adult RSV Vaccination Programme

Objective: RSV is a significant contributor to severe acute respiratory infection (SARI) admissions. Despite national recommendations for RSV vaccination in Ireland, they have not been implemented due to cost concerns and evidence gaps. We assessed RSV-SARI tertiary healthcare engagement to determine healthcare utilisation costs and potential savings in patients following RSV vaccination. Methods: RSV SARI admissions over two winter seasons (2024/25 and 2025/26) at a tertiary centre in Ireland were assessed. Sociodemographic and disease-specific variables were recorded, and their relationship with outcomes investigated. Potential cost offsets which may present following a successful RSV vaccination campaign were calculated. Results: There were 168 RSV admissions during the study (54% aged ≥75). Median length of stay was 6 days and was significantly longer in patients aged ≥75. Having a chronic neurological disease was associated with increased length of stay. The 90-day readmission rate was 24%. Vaccinating ≥75-year-olds in the hospital catchment area would cost €3,712,500, while predicted admission avoidance post-vaccination would save €1,197,692, or €111.77 per vaccine administered. Vaccine costs of €49 would be cost-neutral at the hospital level. Conclusions: RSV disproportionately affects patients ≥75 years of age. Projected vaccine cost offsets in this population are substantially different from those previously used to inform national policy.