The U.S. National Institutes of Health is discussing with Pfizer Inc whether the drug maker’s COVID-19 antiviral treatment is researching the need for a longer course to prevent Paxlovid re-infection, top U.S. infectious disease specialist Dr. Anthony Fawcett said Wednesday.
“We’re going to plan to determine if there’s a need for a longer course to determine what studies we’re going to do in the next few days,” Fawcett said at a Covid-19 briefing at the White House.
Growing COVID-19 cases in the United States are increasing the therapeutic use, so far more than 660,000 courses of poxlovid pills have been conducted in the country.
Some patients have reported that COVID symptoms recur after completing a five-day course of treatment and experiencing improvement, but it is not clear exactly how many have experienced such a rebound.
In Pfizer’s clinical trial, about 2% of recipients who received two-drug treatment had an increased viral load after completing the standard course, compared to 1.5% of placebo recipients.
Dr. Ashish Jha, White House’s Covid-19 response coordinator, said the data was compiled when Delta was the dominant form of the coronavirus, and it is unclear whether re-infection is now predominant in Omicron.
Jha said re-infections do not appear to hinder Paxlovid’s hospitalization and ability to reduce COVID-19 mortality.
Pfizer suggested that a second five-day course of Paxlovid could treat re-infection. The U.S. Food and Drug Administration says there is currently no evidence to support a second five-day course or a 10-day course of pills.
(Reporting edited by Michael Erman by Bill Barcrott)