BACKGROUND: Nearly one-third of United States (US) adults aged 18-59 years are at increased risk of severe RSV disease due to the presence of at least one chronic medical condition. This study estimated the potential clinical and economic impact of mRNA-1345 in adults aged 18-59 years at increased risk over 3 years in the US. “Increased risk” was defined as having at least one of the following: chronic cardiovascular disease, chronic lung disease, chronic kidney disease, chronic liver disease, diabetes mellitus, HIV, or severe obesity.
METHODS: A decision-analytic model was developed to compare one dose of mRNA-1345 administered before the RSV season to no vaccination. Incidence rates and cost inputs were derived from published literature. Vaccine efficacy and waning assumptions were based on phase 2/3 pivotal trial data (~19 months of median follow-up). Outcomes included medically attended (MA) RSV cases and direct and indirect costs (2023 US dollars) from RSV illness. Outcomes were analyzed separately for ages 18-49 and 50-59 years at increased risk. Influenza vaccine coverage rates were used as proxies for RSV vaccine coverage.
RESULTS: In adults aged 18-49 and 50-59 years at increased risk, mRNA-1345 could avert 218,000 (17% reduction) and 374,000 (13% reduction) MA cases, respectively, compared to no vaccination over 3 years. This includes a reduction of 40,000 RSV hospitalizations and nearly 1,700 deaths across both age groups. Among adults 18-49 and 50-59 years at increased risk, mRNA-1345 could avert $1,566 million in total costs ($1,015 million in direct; $551 million in indirect cost) and $1,162 million in total costs ($765 million in direct; $398 million in indirect cost), respectively.
CONCLUSIONS: Vaccinating adults aged 18-59 years at increased risk of severe RSV disease could substantially alleviate the public health burden of RSV, potentially saving over $1.7 billion in direct treatment cost and nearly $1 billion in productivity losses.
