How common is a Paxlovid rebound?

Paxlovid is an anti-viral pill used to treat covid-19. The Department of Health and Human Services says about 4 million courses of Paxlovid have been administered -- But some people who have taken the antiviral pill are testing positive a second time. Dr. Carlos del Rio, Executive Associate Dean, Emory University School of Medicine//"We know people who are older are more likely to rebound."