The U.S. Food and Drug Administration on Thursday authorized Merck & Co's antiviral pill for COVID-19, after giving the go-ahead to a similar treatment from Pfizer Inc. a day earlier.

Merck's drug, molnupiravir, developed with Ridgeback Biotherapeutics, was shown to reduce hospitalizations and deaths by around 30 percent in a clinical trial of high-risk individuals early in the course of the illness.

The agency authorized the oral drug for the treatment of mild-to-moderate COVID-19 in adults who are at risk for severe disease.