The antiviral drug Pfizer vs. COVID-19 Paxlovid has been described as a breakthrough in disease control that promises fast, convenient and effective protection against serious diseases in the elderly and other people at increased risk of contracting the virus.

But in recent weeks, there has been growing concern that some people who have completed a five-day prescription course are getting sick and will soon get a positive result again. Among them this week was Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston, an expert who frequently spoke on national news.

“I thought COVID was over,” Hotez tweeted on Tuesday, saying that five days after completing the Paxlovid course he had a runny nose, sore throat and a “cry for antigen +” on COVID-19. “Eventually we’ll figure it out, but it’s still a puzzle.”

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

Is the virus, whose mutated variants have partially evaded vaccine protection and caused several rounds of boosters, also finding ways to defeat the latest miracle cure allowed for emergency use just five months ago? Should I take Paxlovid?

Medical experts say they do not know exactly why some people who defeated COVID-19 infection with Paxlovid tested positive for the virus and felt bad again shortly after taking the medication. But they say that taking antiviral therapy is still worth it.

Representatives of the White House said on Wednesday that the drug is becoming an increasingly important weapon in the fight against coronavirus, and 20,000 prescriptions are issued daily across the country. They also urged people not to overreact to reports of rebound infections.

“I am excited by this whole conversation that people will lose the forest behind the trees and lose the benefits of Paxlovid,” said Dr. Peter Chin-Hong, a professor of medicine and infectious disease specialist at UCSF. “It seems to be the exception rather than the rule, and so far most people are recovering on Paxlovid and faster.”

Chin-Hong and others described Paxlovid and another antiviral drug, molnupivir Merck, allowed at about the same time as changes in the fight against COVID-19, offering a safe, effective and convenient way to reduce the risk of severe infection or dying.

Antivirals are allowed for people 12 years of age and older who are considered to be at higher risk for COVID-19 infection either because of diseases such as obesity or diabetes, or simply because they are older.

At a time when vaccine protection against new options is weakening, and monoclonal antibodies that require intravenous infusion are losing their effectiveness, antiviral drugs prescribed at the onset of symptoms and taken at home can help defeat the infection. Pfizer blocks an enzyme needed for the virus to reproduce, and has been found to reduce the risk of hospitalization or death in high-risk adults by 89%. The effectiveness of the drug Merck is 30%.

In the Gulf region and the rest of the country, there is an increase in cases again. Federal and state officials continue to urge Americans to do additional injections and wear face masks in crowded places.

“There’s nothing to worry about right now,” Gov. Gavin Newsom said of the rise in the number of cases when he received his second vaccination from Moderna in Bakersfield on Wednesday.

“This diminishing immunity is – I don’t mean to worry – but something we need to control,” Newsom said. “The best protection against serious illness and hospitalization is vaccination and training.”

Both Pfizer and the Food and Drug Administration noted that during clinical trials, about 1-2% of patients who completed five days of Paxlovid treatment were positive after an initial negative test or showed elevated virus levels. But they said the same thing was happening at the same rate among those taking placebo instead of the drug. And none of the claimed heels led to a serious illness.

“So it’s unclear at the moment that this has to do with drug treatment,” said Dr. John Farley, director of the FDA’s Office of Infectious Diseases. instructions for healthcare professionals posted online. “The main thing was that there was no increase in hospitalization, death or the development of drug resistance.”

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

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

Wachter said that his wife “absolutely” should have accepted Paxlovid – they are over 60 – despite the possibility of a rebound. Will prolonged pill intake reduce this chance? “I would not take another course of Paxlovid until we see real evidence to support it,” he tweeted.

Pfizer spokesman Keith Longley said “further evaluation is still needed” and the company is monitoring data from ongoing clinical trials and safety oversight. “We remain very confident in its clinical efficacy in preventing severe outcomes of COVID-19 in high-risk patients.”

The state announced Wednesday that it will open 146 telemedicine sites across the state in the next few weeks where people can get screened and, if eligible, get antiviral drugs and other medications. Check it out here to find a location or visit: covid-19-test-to-treat-locator-dhhs.hub.arcgis.com.