U.S. authorities will test the effectiveness of Paxlovid in treating protracted COVID

The U.S. National Institutes of Health's $1 billion RECOVER initiative has chosen Pfizer Inc.'s antiviral drug Paxlovid as the first drug to be studied in patients with long-term COVID, according to Reuters.

The randomized, placebo-controlled study will test Pfizer's drug or placebo on 1,700 volunteers in the age group 18 and older, according to information about the study posted on Clinicaltrials.gov.

The study, scheduled to begin Jan. 1, is being supervised by the Duke Clinical Research Institute.

The study will examine the underlying theory of the cause of the lingering course of COVID, that fragments of the virus remain in some people's tissues, which causes the lingering manifestations of the disease.

Paxlovid, which combines Pfizer's new pill and the old antiviral drug Ritonavir, is currently approved for use in the first days after COVID infection to prevent a severe course of the disease in high-risk patients.