Two COVID-19 Antiviral Pills Granted EUA

December 24, 2021

This week, the FDA granted EUA for two COVID-19 oral antiviral pills, which will be added as a second treatment protocol for COVID-19. Up until now, monoclonal antibodies have been the only authorized treatment for patients with COVID-19.

Currently, Pfizer’s COVID-19 antiviral pill has been authorized for high-risk adults and children 12+ years in age. In a clinical trial, Paxlovid reduced the risk of hospitalization and death by 89% when taken within three days of experiencing symptoms, and 88% when taken within five days. Paxlovid has shown a significantly higher rate of efficacy than Merck’s antiviral pill, Molnupiravir, which reduced the risk of hospitalization and death by 30% in a Merck clinical trial. In order to receive a Pfizer regimen, patients will need to receive a positive test result and get a prescription within five days upon the onset of symptoms. The regimen includes 30 pills taken over five days. Patients taking the following medications should not take Paxlovid.

Molnupiravir has been authorized for adults 18+ in the US who are at risk of severe disease, of which other treatment options are not available, and taken within 5 days upon the onset of symptoms. This is due to the fact Merck’s pill has a relatively low efficacy rate compared to Paxlovid and monoclonal antibody treatments. Additionally, “Molnupiravir is not authorized for use in patients younger than 18 years of age because molnupiravir may affect bone and cartilage growth. It is not authorized for the pre-exposure or post-exposure prevention of COVID-19 or for initiation of treatment in patients hospitalized due to COVID-19 because benefit of treatment has not been observed in people when treatment started after hospitalization due to COVID-19.” Those who are pregnant should not take Merck’s antiviral pill, as it may lead to birth defects. Those who may become pregnant should use contraception while taking the antiviral pills and for four days after the final dose; male partners of women who could become pregnant should use contraception during the treatment protocol and for at least three months after the final dose.

During an ACIP meeting regarding Molnupiravir, panelists questioned the safety of Merck’s pill given its mutagenic qualities – Merck’s pill introduces errors into the virus’s genetic code to prevent replication (1). The regimen includes 40 pills taken over five days.