Breakthrough infections reported in some COVID-19 patients treated with Paxlovid

About 20,000 Americans a day are now being prescribed Paxlovid, an antiviral that is close to 90% effective at preventing hospitalization and death in higher risk people infected with COVID-19.

But, some patients are reporting rebound infections, developing symptoms or testing positive days after they finish the 5-day course of treatment.

White House COVID-19 response coordinator Dr. Ashish Jha says about 2% of the patients in clinical trials in the Paxlovid group, and 1.5% in the placebo, reported rebound symptoms, but that was with the less contagious Delta variant.

"So, the question is: Is this more common with Omicron," Dr. Jha says.  "We’re actually doing a lot of work right now to try to sort that out.  We’re talking to health systems, getting real-world experience data.  But if you think about it: If you have, you know, 20,000 people getting Paxlovid every day, that would mean that about — even if it was only still 2 percent, that would mean 400 people are having rebound every day.  So it is hard to know exactly how often it happens."

The FDA says it is aware of reports rebound COVID-19 infections in some patients treated with Paxlovid, But the agency says there is no evidence that extending the Paxlovid course of treatment beyond 5 days would be beneficial.

"I think the key points — or a couple of key points that are really important: One is that the people who have that rebound are not getting particularly sick, are not ending up in the hospital," Dr. Jha says.  "If the goal of this treatment, which it was, was to prevent hospitalizations and deaths, it is doing that incredibly well. So, the rebound issue is something we're looking at very carefully, but it is not leading to people getting particularly sick."

If you develop COVID-19 symptoms or test positive for COVID-19 after being treated with Paxlovid, alter your doctor.

The CDC also recommends putting on a mask to protect others around you.