The Potential Public Health and Economic Benefit of an mRNA-Based Respiratory Syncytial Virus Vaccine Among Adults ≥60 Years in the United States

OBJECTIVES: In older adults, respiratory syncytial virus (RSV) is an important cause of lower respiratory tract disease (LRTD), which can result in hospitalization and death. The study estimated the potential clinical and economic impact of a recently approved RSV vaccine, mRNA-1345, in ≥60 year-olds over a two-year timeframe in the United States (US).

METHODS: A decision-analytic model was developed to compare no vaccination to a single dose of mRNA-1345 administered before the RSV season. Based on phase 2/3 clinical trial data (18.8-months of median follow-up period), mRNA-1345 is assumed to prevent RSV-acute respiratory disease (ARD) and reduce RSV-LRTD, and RSV-LRTD hospitalizations amongst those developing infections. Influenza vaccine coverage rates were used as a proxy for RSV coverage (60-64y: 50.6%; ≥65y: 69.8%). The model was calibrated to match hospitalization rates adjusted for underdetection from a meta-analysis (McLaughlin 2022).

RESULTS: Without vaccination, the model predicted 8.9 million RSV-ARD cases, including 2.6 million RSV-LRTD cases over two-years. mRNA-1345 reduced RSV-ARD cases by 2.5 million (28%) and RSV-LRTD cases by 1.0 million (40%). Without vaccination, the model predicted 309,000 RSV-LRTD hospitalizations and 23,400 in-hospital deaths over two-years. Vaccination reduced hospitalizations and deaths by 133,500 (43%) and 10,100 (43%), respectively. The numbers of vaccines required to be administered (number needed to vaccinate; NNV) to prevent one RSV-ARD case was 20; NNVs to prevent one RSV-LRTD case, hospitalization, and death were 49,382, and 5,045, respectively. Over two-years, total RSV-related costs without vaccination were $13,200 million(M) (healthcare: 11,600M; productivity: 1,500M); mRNA-1345 vaccination would reduce these costs by $4,700 million (healthcare: 4,300M; productivity: 400M) (35%).

CONCLUSIONS: mRNA-1345 could substantially reduce RSV-related public health burden in adults ≥60 years. If RSV vaccination coverage in the US was increased to match influenza, then the model predicted reductions of 43% for RSV-LRTD hospitalizations and deaths and 35% of total RSV-related costs.