Some COVID patients treated with Paxlovid see symptoms return after recovery

BOSTON - The Centers for Disease Control and Prevention has issued a health advisory that people who have taken the prescription medication Paxlovid for COVID-19 need to isolate again if their symptoms return. 

Paxlovid is a pill that is offered to patients at higher risk of COVID-related complications. It needs to be started within 5 days of the onset of COVID symptoms. 

It's generally well-tolerated and can help prevent hospitalization and death from COVID-19. But a small percentage of patients treated with Paxlovid will experience a rebound of their COVID symptoms 2-to-8 days after initial recovery. The symptoms are usually mild and there have been no reports of severe disease. 

But patients will often test positive again even after having tested negative. It's not clear whether this is the natural history of the illness in some people with COVID. It does not appear to be due to resistance to the medication or reinfection with the coronavirus. 

However, because the virus is detectable once again in these patients they could be contagious, so the CDC is now saying they should isolate again for at least 5 days and wear a mask for 10 days after the rebound symptoms started.