Objectives: Antiviral treatments for early intervention in patients with mild-to-moderate COVID-19 are needed as a complement to vaccination. We sought to estimate the change in COVID-19 cases, deaths, and direct healthcare costs over 12 months following introduction of a novel antiviral treatment which reduces symptomatic disease and transmission probabilities when used as a complement to vaccines.

Methods: A time-dependent, state transition (semi-Markov) cohort model was developed to simulate infection progression in individuals with COVID-19 in three U.S. states with varying levels of vaccine uptake (Alabama, North Carolina, and Massachusetts) and at the national level between June 2020 and May 2021. The hypothetical cohort of patients entering the model progressed through subsequent health states after infection. Costs were assigned to each health state. Number of infections/ vaccinations per day were incorporated into the model. Simulations were run to estimate outcomes (cases by severity, deaths, and direct healthcare costs) at various levels of adoption of an at-home, antiviral therapy at the state and national-levels and across three levels of clinical benefit reflecting a decline in the duration of symptomatic disease by 1.2, 2.4 (base case), or 3.6 days. Results from an early feasibility study of RD-X19, a novel device for the treatment of COVID-19, were used as the base case.

Results: Ten percent adoption reduced total infections/deaths/direct healthcare costs by 10,059/275/$69 million in Alabama, 21,092/545/$135 million in North Carolina, and 16,670/415/$102 million in Massachusetts over 12 months. Sensitivity analyses found that even with symptomatic days reduced by only 1.2 (compared to no treatment), early intervention results in meaningful reduction in infections, deaths, and direct healthcare costs.

Conclusion: At-home, antiviral treatment options like RD-X19 that decrease both symptomatic days and transmission probabilities can be used in concert with vaccines to reduce COVID-19 cases, deaths, and direct healthcare costs.