Considered a game-changer when it was authorized in December because of its strong performance in lowering the risk of severe Covid-19, Paxlovid — in combination with vaccines and boosters — is thought to be one of the best ways to protect people at high risk for severe illness.
Paxlovid is an antiviral medication from Pfizer that uses two drugs: nirmatrelvir and ritonavir. It comes in pill form.
The standard regimen is three pills twice daily for five days.
Biden’s risk for severe disease
Biden’s age — 79 — puts him at risk for severe Covid-19. But the US Centers for Disease Control and Prevention says older adults who are fully vaccinated and boosted significantly reduce their risk of hospitalization and death.
Biden is double-boosted. He got his initial vaccination series before his inauguration in January 2021. He got his first booster in September and his second booster March 30.
Biden’s symptoms are mild. He has a runny nose, an occasional cough and some fatigue.
How does Paxlovid work?
Paxlovid suppresses the coronavirus, blocking an enzyme that helps the virus reproduce inside the body.
As with all antivirals, the treatment is thought to work best if people start taking it within five days of their first symptoms.
How successful is it?
However, the drug was tested in unvaccinated people during the Delta variant surge, so the results could look different for people who take the pills now, with the Omicron variant dominant.
“Joe Biden is vaccinated and twice boosted, that in and of itself decreases his risk of severe disease, hospitalization or death,” Dr. Megan Ranney, an emergency physician and academic dean of public health at Brown University, said Thursday. “You add on to it Paxlovid, which reduces — even in vaccinated people — that risk of hospitalization by another 80% to 90%, and the chance of anything bad happening to him is virtually zero.”
What about side effects?
Doctors say the medication is usually well-tolerated.
What about a rebound?
“There have been people who have had Paxlovid relapse. That is, although Paxlovid suppresses [symptoms] for a period of time while you’re taking it, five days, after that, some people get a recurrence of some of their symptoms. So we’ll just have to watch that,” Dr. William Schaffner, a professor in the division of infectious diseases at Vanderbilt University Medical Center, said Thursday.
Rebound cases have been reported between two and eight days after initial recovery. Most people who had new symptoms said they resolved in about three days, even without additional treatment.
Ranney and other doctors say they don’t like to think of it as a rebound infection. Rather, Paxlovid does a good job of suppressing the virus and preventing the damage it can do, but it’s possible that the virus is not fully eliminated from the body and re-emerges.
Some scientists think that some people metabolize Paxlovid more quickly than others and that they may need a longer course of treatment. Research is still underway.
“We’re not seeing folks who end up with those symptoms with a need for hospitalization after taking Paxlovid, so the term ‘rebound’ I don’t like because it scares people away from taking Paxlovid,” Ranney said.
White House Covid-19 Response Coordinator Dr. Ashish Jha downplayed concerns over the potential that Biden might rebound while taking Paxlovid.
“The best clinical data we have suggests it happens about 5%, 7% of the time,” Jha said Friday. “It’s pretty infrequent, and the good news is, even when that happens, people end up doing just fine.”