Closeup of man getting ready to take a pill with water

The Food and Drug Administration is expected to authorize the use of two antiviral COVID-19 pills this week, possibly as early as today, according to Bloomberg News, citing sources familiar with the matter.

Pfizer’s Paxlovid and Merck’s molnupiravir are in line for emergency use authorization. The drugmakers earlier this fall posted promising clinical trials results showing the pills substantially cut COVID-19 hospitalization and mortality risk in patients diagnosed with COVID-19. 

Molnupiravir has been found to cut COVID-19 hospitalization and mortality risk by 30% in at-risk, non-hospitalized adult patients with mild-to-moderate COVID-19. FDA advisers recommended its authorization in a close vote in early December. 

Paxlovid, meanwhile, reduced the rate of hospitalization and death from COVID-19 by nearly 90% in clinical trials, drugmaker Pfizer has announced. In lab tests, both drugs have shown potential effectiveness against mutations of the virus designated as variants of concern.

Antivirals block the ability of a virus to replicate and spread further throughout the body. 

The drugs are designed to be taken by adults at high risk of severe COVID-19 illness within days after symptoms arise or a patient tests positive for COVID-19 infection.

Treatment in pill form — taken to prevent or lessen the effects of the disease — could offer unprecedented convenience when compared to the limited treatment options currently available in the United States.

Among already-approved COVID-19 treatments, the Food and Drug Administration has authorized the use of the antiviral remdesivir (Veklury). That drug is approved only for hospitalized patients and must be delivered intravenously. Monoclonal antibody treatments, offered to nonhospitalized, at-risk adults to prevent severe COVID-19 outcomes, must also be delivered intravenously or, as in the case of REGEN-COV, subcutaneously in a series of four injections.

Because antiviral drugs like Paxlovid and molnupiravir work by interfering with the RNA in the SARS-CoV-2 virus, their potential to have an adverse effect on human DNA or RNA are key concerns in authorizing these pills, experts say.