Antiviral Efficacy of Molnupiravir for COVID-19 Treatment

Abstract

The ongoing global pandemic of COVID-19 poses unprecedented public health risks for governments and societies around the world, which have been exacerbated by the emergence of SARS-CoV-2 variants. Pharmaceutical interventions with high antiviral efficacy are expected to delay and contain the COVID-19 pandemic. Molnupiravir, as an oral antiviral prodrug, is active against SARS-CoV-2 and is now (23 February 2022) one of the seven widely-used coronavirus treatments. To estimate its antiviral efficacy of Molnupiravir, we built a granular mathematical within-host model. We find that the antiviral efficacy of Molnupiravir to stop the growth of the virus is 0.56 (95% CI: 0.49, 0.64), which could inhibit 56% of the replication of infected cells per day. There has been good progress in developing high-efficacy antiviral drugs that rapidly reduce viral load and may also reduce the infectiousness of treated cases if administered as early as possible.

Keywords: COVID-19; Molnupiravir; SARS-CoV-2; antiviral efficacy.

Figure 1

Within-host modeling. We model the replication dynamics of SARS-CoV-2 viruses within an infected individual. Uninfected cells (U) progress to infectious cells (I) with infection rate $\beta$, and finally release viruses (V) with replication rate p.

Figure 2

Viral load following Molnupiravir treatment. The estimated means and 95% CI of virus titer from the fitted within-host model track the mean values of empirical observations (blue circles) among patients treated with (A) placebo, or (B) Molnupiravir. Day zero corresponds to the beginning of the treatment.