A collection of pink pills, used to explain Paxlovid

Paxlovid is free, highly effective, but what about COVID-19 rebounds?

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President Biden took Paxlovid when he was diagnosed with COVID-19. So did his vice president and their chief COVID-19 adviser, Anthony Fauci.

Both Biden and Fauci had a quick recovery, but both men also suffered a rebound infection days afterward. Biden reported a mild cough the second time, while Fauci said his second bout was worse than the first.

It’s likely that the infection re-emerges in older patients because the virus burrowed into tissues, where the anti-viral could not easily penetrate, says Jon Albrecht, RPh, MHA, BCNSP, FASHP, vice president of Pharmacy Services for Methodist Health System.

“The coronavirus can be deep-seated within tissues,” Albrecht says. “So if you stop taking the drug before the virus is fully suppressed, then it starts to replicate again.”

The Centers for Disease Control and Prevention issued a health alert in May 2022, saying rebound symptoms were typically mild and no cases were severe. Fauci was prescribed a second five-day course and said the drug did exactly what it was supposed to do.

“It’s not meant to prevent you from rebounding,” Dr. Fauci told The New York Times. “It’s meant to prevent you from being hospitalized. I’m 81 years old, I was at risk for hospitalization, and I didn’t even come close to being sick enough to be hospitalized.”

Here’s what else you should know about this “game-changer” that’s become the go-to treatment for high-risk patients:


First approved for emergency use in December, Paxlovid was in high demand during the winter surge. Now, it’s widely available, with a doctor’s prescription, and pharmacists are more worried that thousands of doses will go to waste.

“We have it at all Methodist’s retail pharmacies,” Albrecht says of the 30-capsule, five-day oral medication. “And the drug is free.”

You don’t have to be the most powerful man in the free world to get a prescription for Paxlovid, but this anti-viral medication is not for just anyone either.

“Paxlovid is for people over 65 with no other qualifications, or people 12 and older who are at higher risk,” Albrecht says.

That’s because the U.S. government bought 20 million courses of Paxlovid in April 2022 to be distributed at selected pharmacies.

Educational scientific image of virus molecules


Paxlovid consists of two distinct drugs: nirmatrelvir, which stops the infection in its tracks by inhibiting an enzyme that the coronavirus needs to replicate, and ritonavir, a drug that has been used to treat HIV/AIDS that prevents the liver from metabolizing nirmatrelvir so it stays in the body longer.

“What we’re trying to do is prevent the virus from replicating,” Albrecht says, “whether you’re talking about Tamiflu with the flu virus, or whether you’re talking about COVID-19.”

And like Tamiflu for flu, the most familiar anti-viral, Paxlovid must be taken within five days of experiencing COVID-19 symptoms.

“If you have too much virus in your body, it’s not going to be as effective,” Albrecht says.

Someone holding a container of beige pills, with three of them taken out


Paxlovid isn’t the only anti-viral approved for treating patients at high risk for COVID-19. But it’s proved to be the most effective – by far.

Remdesivir, the only COVID-19 anti-viral treatment that has gained the full approval of the FDA, has been part of our COVID-19 arsenal since early in the pandemic. But it must be administered by IV for three consecutive days, so its use has been reserved for hospitals, assisted-living facilities, and home healthcare.

“We probably would use it more if it was easier to administer,” Albrecht says.

Molnupiravir is an oral medication that hit the market a month ahead of Paxlovid. Like its competitor, it prevents the virus from multiplying and must be taken for five days, within five days of symptom onset.

But both anti-virals are not equal: Molnupiravir is about 30% effective at preventing hospitalizations, data indicate, whereas Paxlovid reduced the risk by nearly 90%. That lower efficacy has made doctors reluctant to prescribe molnupiravir unless Paxlovid is unavailable.

A stock photograph of a woman in bed, sitting against the headboard with her eyes closed, holding her forehead with her fingertips


One downside of Paxlovid is the laundry list of other medications it can interact with, many of them drugs that older adults depend on.

That’s because the same ingredient that pumps up the anti-viral component of Paxlovid also gives a potentially unsafe boost to drugs that treat heart arrhythmia, cancer, and epilepsy, among others.

Drugs that treat cancer, high cholesterol, and an enlarged prostate are also on the list, as are blood thinners, which can reach unsafe levels in the body because the drug interferes with their metabolism. President Biden reportedly switched to low-dose aspirin and stopped taking a blood thinner and cholesterol drug during his treatment.

It’s wise to share a list of your medications with a doctor or pharmacist before seeking a prescription for the anti-viral.

A COVID-19 test with two red lines under the C and T arrows, expressing a positive result


Treating a potentially serious infection is no substitute for preventing it, so being up to date on your COVID-19 vaccinations (including those all-important boosters) is just as important as ever.

The vaccines may not prevent you from getting sick, especially with the highly contagious BA.5 variant going around, but they should protect you from the worst effects of COVID-19, potentially including “long COVID.”

And remember, medications like Paxlovid have a very short window of effectiveness, so if you’re at high risk and you feel sick, get tested as soon as possible. Don’t shrug off your symptoms as allergies or a run-of-the-mill cold.

“Better safe than sorry,” Albrecht says. “Go get tested and check in with your doctor. They will know what to do.”

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