PURPOSE: This modeling study estimated the potential population-level health and economic impact of including NVX-CoV2373, an investigational COVID-19 vaccine, as a booster vaccine option for previously vaccinated adults (18 years or older) in the United States (US).
METHODS: A decision-analytic Markov model was developed to estimate COVID-19–related cases, hospitalizations, and deaths with and without NVX-CoV2373 as a booster vaccine option for adults in the US. The model population was stratified by age, with health states including susceptible, detected infection, long COVID-19, and recovered. The severity of COVID-19 outcomes within the detected infection state was modeled based on the highest level of care required. Vaccine efficacy was sourced from published phase 3 clinical trials, based primarily on the Wuhan variant, and was assumed to wane equally for all vaccines based on observed real-world data. Booster vaccination efficacy (homologous or heterologous) was modeled based on the manufacturers’ primary vaccination series. Other model inputs were sourced from published literature or derived from publicly available data from the US Centers for Disease Control and Prevention. The cost per dose was assumed to be equal for all booster vaccines. We compared key outcomes over a 1-year time horizon for the mix of booster vaccines currently authorized in the US and a vaccine mix including NVX-CoV2373 as a booster option.
RESULTS: A 5% increase in booster vaccine coverage among the 200 million fully vaccinated adults in the US, allocated to NVX-CoV2373 market share, reduced hospitalizations and deaths due to COVID-19 by approximately 26,000 and 4,500, respectively. The increase in coverage resulted in additional vaccination costs of $566M but reduced direct medical costs by $562M. Figure 1 illustrates the impact of including NVX-CoV2373 as a vaccine option on incremental hospitalizations across a range of coverage and market share assumptions. Each additional percentage point increase in coverage reduced COVID-19 hospitalizations and deaths by approximately 0.5% in the population over 1 year.
CONCLUSIONS: Our results suggest that including NVX-CoV2373 as a COVID-19 booster vaccine option for adults in the US has the potential to reduce hospitalizations and deaths because of the anticipated increase in vaccine coverage. Increases in vaccination costs due to higher coverage were predicted to be almost completely offset by reductions in direct medical costs.
