NIH in talks with Pfizer to study a longer course of COVID drug Paxlovid, Fauci says

Following reports of rebounding COVID-19 symptoms in people who took Pfizer's antiviral Paxlovid, the National Institutes of Health and the company are discussing testing a longer course of the antiviral, White House Chief Medical Officer Anthony Fauci, M.D., said Wednesday.

“We’re going to be planning what studies we’re going to be doing relatively soon, within the next few days,” Fauci said during a White House COVID-19 briefing.

More than 660,000 courses of Paxlovid have been administered in the U.S. so far. Some patients who took Paxlovid have reported that their COVID-19 symptoms returned after completion of the five-day treatment, but it’s unclear exactly how many have dealt with rebounding symptoms.

In Pfizer’s clinical trial, around 2% of recipients who received the treatment experienced an increase in viral load after completing the standard course. That's compared with 1.5% among placebo recipients. The small difference makes it unclear whether the patients' viral load increase was in any way related to the treatment.

To curb reinfections, Pfizer CEO Albert Bourla, Ph.D., recently suggested a second five-day course of the treatment. The FDA quickly rebutted this claim, saying there is no evidence to support taking more pills than listed on the drug label.

The U.S. wants to increase the drug's availability and is working with Pfizer to increase supply.