P-603. Potential Public Health Impact of Respiratory Syncytial Virus (RSV) Vaccines for Prevention of RSV Among Older Adults in the United States

Abstract Background Two United States (US) Food and Drug Administration-approved vaccines are recommended by the Advisory Committee for Immunization Practices for prevention of lower respiratory tract disease (LRTD) due to respiratory syncytial virus (RSV) among US adults aged ≥ 60 years and another vaccine for adults is under regulatory review. We evaluated the potential public health impact of vaccines for prevention of RSV-LRTI in older adults. Methods A cohort model was employed to depict clinical outcomes and economic costs of RSV-LRTD over two years with use of alternative vaccines (ie, Pfizer’s RSVpreF, GSK’s RSVpreF3, Moderna’s mRNA-1345 respectively, vs no intervention) among a cohort of 2.4M adults aged ≥ 60 years in a hypothetical US health plan with 10M beneficiaries. Clinical outcomes were projected (monthly) based on age, comorbidity profile (ie, with vs without chronic or immunocompromising medical conditions), RSV-LRTI disease rates (requiring hospitalization [H], emergency department [ED], or physician office/hospital outpatient care [PO/HO]), calendar month, case fatality rates (RSV-H only), and vaccination status (23.6% uptake in October of model year 1 only). Initial vaccine effectiveness (VE) and waning of VE was derived from published or presented Phase III clinical trial data. Economic costs were generated based on cases and corresponding unit costs. Results Without use of RSV vaccine, 14,687 hospitalizations, 11,201 ED encounters, 132,472 PO/HO visits, and 1,230 RSV-related deaths are projected to occur over two years. Pfizer’s RSVpreF would result in a 22,301-case reduction (RSV-H: 2,713; RSV-ED: 2,069; RSV-PO/HO: 17,519) and 227 fewer deaths; total medical care costs would be lower by $86.0M (RSV-H: $64.2M; RSV-ED: $7.4M; RSV-PO/HO: $14.4M) (Table). GSK’s RSVpreF3 would reduce cases by 16,183, deaths by 205, and medical care costs by $76.8M. Moderna’s mRNA-1345 would reduce cases by 9,357, deaths by 112, and medical care costs by $43.2M (based on single-season efficacy data). Conclusion RSV vaccines have the potential to substantially reduce the clinical and economic burden of RSV-LRTI in older adults. Of the three vaccines, Pfizer’s RSVpreF would provide the greatest benefit due to its high 2-year efficacy. Disclosures Ahuva Averin, MPP, Pfizer Inc: Advisor/Consultant Reiko Sato, PhD, Pfizer Inc: employee|Pfizer Inc: Stocks/Bonds (Private Company) Erica Chilson, PharmD, Pfizer Inc: Employee|Pfizer Inc: Stocks/Bonds (Public Company) Mark Atwood, MS, Pfizer Inc: Advisor/Consultant Erin Quinn, BS, Pfizer Inc: Advisor/Consultant