COVID-19 may “return” after taking antiviral Paxlovid
COVID-19 may “return” after taking antiviral Paxlovid

COVID-19 may “return” after taking antiviral Paxlovid

Pfizer’s COVID-19 antiviral drug Paxlovid has been hailed as a breakthrough in the fight against the disease, promising rapid, convenient and dramatic protection against serious illness in older adults and others at higher risk for the virus.

But in recent weeks, there has been growing concern that some people who end the five-day course with prescription pills will get sick and test positive again soon after. Among them this week was Dr. Peter Hotez, dean of the National School of Tropical Medicine at Houston’s Baylor College of Medicine, an expert who was frequently featured in national news broadcasts.

“Well thought COVID was over,” Hotez tweeted Tuesday, reporting that five days after completing his Paxlovid course, he had a runny nose, sore throat and “antigen test that screamed +” for COVID-19. “We will eventually find out, but still a puzzle.”

UC San Francisco Medical Department Chairman Dr. Bob Wachter, who shared his wife’s journey through COVID-19 disease and Paxlovid treatment on social media with her permission, added on Wednesday that they were concerned enough about the odds of a “rebound infection” as they watched TV together wearing masks – with their windows open.

Does the virus, whose mutated variants have partially evaded vaccine protection and prompted calls for more rounds of boosters, also find ways to defeat the latest miracle cure, approved for emergency use just five months ago? Is Paxlovid still worth taking?

Medical experts say they do not know for sure why some people who fight back a COVID-19 infection using Paxlovid test positive for the virus and feel ugly again shortly after quitting the drug. But they say it’s worth taking the antiviral therapy, no matter what.

White House officials reported Wednesday that the drug has become an increasingly important weapon in the fight against coronavirus, with 20,000 prescriptions being printed a day across the country. They also urged people not to overreact to reports of rebound infections.

“My concern throughout this conversation is that people will lose the forest to the trees and lose the benefit of Paxlovid,” said Dr. Peter Chin-Hong, Professor of Medicine and Specialist in Infectious Diseases at UCSF. “It seems to be the exception rather than the rule, and so far most people are getting better at Paxlovid and faster.”

Chin-Hong and others have described Paxlovid and another antiviral drug, Merck’s molnupiravir, approved around the same time as game-changers in the COVID-19 battle, offering a safe, effective and convenient way to reduce the risk of an infected person becomes seriously ill or dying.

The antiviral drugs are approved for people 12 years and older who are considered to have a higher risk of COVID-19, either because of health conditions like obesity or diabetes, or simply because they are older.

At a time when vaccine protection is declining against new variants and monoclonal antibodies requiring intravenous infusion are losing their effectiveness, antiviral drugs prescribed at the onset of symptoms and taken at home can help fight back infection. Pfizer’s drug blocks an enzyme that the virus needs to reproduce, and it was shown to reduce the risk of hospitalization or death in high-risk adults by 89%. The efficacy of the Merck drug is 30%.

Bay Area and the rest of the country are seeing cases rise again. Federal and state officials continue to urge Americans to get booster shots and wear face masks in crowded environments.

“It’s nothing to worry about at the moment,” Governor Gavin Newsom said of the rising number of cases when he received his second Moderna booster shot on Wednesday in Bakersfield.

“This declining immunity is one thing about – I do not want to say worrying – but something we need to monitor,” Newsom said. “The best protection against serious illness and hospitalization is to be vaccinated and boosted.”

Both Pfizer and the Food and Drug Administration have noted that during clinical trials, approximately 1-2% of patients who completed the five-day Paxlovid treatment tested positive again after first testing negative, or showed increased levels of the virus. But they said the same thing happened at similar rates among those who received placebo instead of the drug. And none of the reported rebounds led to serious illness.

“So it is unclear at this time that this is related to drug treatment,” said Dr. John Farley, Director of the FDA’s Office of Infectious Diseases, i guidance for healthcare professionals posted online. “Most importantly, there was no increased incidence of hospitalization or death or development of drug resistance.”

Chin-Hong said the rebound phenomenon is not new and has been seen in other viral infections. But why it happens with COVID-19 and Paxlovid is a mystery, he said.

“So many people have had such a great experience with it,” Chin-Hong said. “In my experience, there was maybe one person who had a rebound, and they did fine, and it was milder.”

Leave a Reply

Your email address will not be published.