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Experts worry COVID pills could hinder vaccine efforts

Doctors say the at-home treatments being considered by federal regulators aren’t a substitute for getting vaccinated.

Paxlovid, Pfizer’s COVID treatment pill, are produced in a laboratory in Freiburg, Germany.PFIZER/NYT

With federal regulators expected to soon clear the first prescription pills to treat COVID-19 at home, some public health experts are worried that unvaccinated people will wrongly believe the new medicines will make shots unnecessary, hindering inoculation efforts that doctors say remain crucial to ending the pandemic.

Infectious disease specialists were buoyed earlier this week when Pfizer announced final results from a clinical trial of its experimental antiviral drug. The data indicated it was 89 percent effective at preventing high-risk COVID patients from being hospitalized or dying. Preliminary laboratory studies also suggested the medicine will hold up against the Omicron variant.


Patients in the study started taking the drug, called Paxlovid, within three days of symptoms appearing, along with an existing HIV medication, for a total of 30 pills over five days. An advisory panel is widely expected to vote this month on whether the Food and Drug Administration should authorize the regimen, although no meeting has been scheduled.

But several public health experts worry that the availability of Paxlovid, and the possible authorization of another experimental drug from Merck that appears to be much less effective, would only harden the resistance of millions of Americans who have yet to get vaccinated. Dr. Scott Ratzan, an expert on vaccine communication who teaches at the City University of New York Graduate School of Public Health, led a recent survey of about 3,000 Americans that highlighted the potential for that scenario.

Of the 753 people in the nationwide survey who as of Nov. 12 hadn’t been vaccinated, 34 percent said they would prefer to treat COVID with a pill, compared with 15 percent who would prefer to prevent the illness by getting vaccinated. Notably, the remaining 51 percent said they didn’t want to take a vaccine or medication and would rather treat COVID at home with sleep, fluids, or over-the-counter treatments.


“The new COVID pills are a big deal, but vaccinations will always be the cornerstone of our response to COVID,” said Ratzan, a former scientific adviser to the Centers for Disease Control and Prevention. “It’s always better to prevent a disease from happening at all. ... Only a vaccine can control the rate at which a virus spreads and mutates.”

Even if antiviral drugs did keep patients with early COVID symptoms from getting dangerously ill, he said, neither the Pfizer nor Merck trials determined whether the medicines prevented other possible consequences of the disease. That includes “long COVID,” a debilitating condition marked by physical and psychological symptoms that last six months or more.

Dr. Irwin Redlener, director of the Pandemic Resource and Response Initiative at Columbia University, said pills that COVID patients could take at home soon after symptoms appear would be a “tremendous game-changer.”

Currently, the only authorized treatments for nonhospitalized COVID patients are monoclonal antibodies, laboratory-produced molecules that act as substitute antibodies that can restore, enhance, or mimic the immune system. Those drugs, whose makers include Regeneron Pharmaceuticals and Eli Lilly, also must be given soon after symptoms appear, but they have several major disadvantages. Perhaps the biggest one is that patients usually have to get the medicine in an hourlong intravenous infusion in a clinical setting, which can be hard to arrange.

Although antiviral drugs would be better, Redlener said, he is “extremely concerned” that their availability might undermine efforts to get more shots into arms.


“Does this give reinforcement to the antivaxxers who say, ‘Why should I get vaccinated? I’ll just go get a prescription?’” said Redlener, a pediatrician. If so, he said, it would prolong the pandemic because parts of the world with stubbornly low vaccination rates would likely spawn new variants after Omicron. “If you understand why the mutations and variants are cropping up, it’s because the virus is allowed to fester in places where [people] are highly unvaccinated,” he said.

Even the most promising antiviral drugs are of limited value, said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine and a vaccine authority. Paxlovid is designed to inhibit viral replication but must be taken within five days of the onset of symptoms, which means getting a COVID test, diagnosis, and prescription quickly.

“You need to take them very early in the virus replication phase of the illness, otherwise they won’t work,” Hotez said. “They are not a substitute for a vaccine. They’re a backstop and not a very efficient one.”

Merck’s experimental drug, molnupiravir, has even more drawbacks. An FDA advisory panel voted 13-10 on Nov. 30 to recommend its use, but the FDA has yet to sign off, and the medicine may have lost some of its luster. Although Merck initially said the drug lowered the risk of hospitalization and death by 50 percent when taken within five days of symptoms starting, the pharmaceutical giant later said its effectiveness fell to 30 percent in an updated analysis.


In addition, several physicians on the advisory panel said they were concerned that molnupiravir might pose more risks than benefits because of how it works. The drug stops the genetic material in SARS-CoV-2 ― the virus that causes COVID ― from replicating itself accurately and inserts mutations that get repeated over and over, ultimately killing the virus.

Some committee members worried the drug could do the same in human cells, particularly in the fetuses of pregnant women. The FDA is considering a blanket restriction on use by pregnant women or only allowing doctors to prescribe the drug to pregnant women in rare cases when they are diagnosed with COVID and at high risk of getting seriously sick.

The US government has paid about $2.2 billion for roughly 3.1 million courses of molnupiravir, with each course requiring 40 pills. Pfizer has reached a deal with the federal government to provide up to 10 million courses of Paxlovid for $5.3 billion, with each course requiring 30 pills.

Not all doctors are fretting over the threat to vaccination efforts.

Dr. Paul Sax, an infectious disease specialist at Brigham and Women’s Hospital, said patients don’t typically turn down vaccines to prevent other contagious diseases simply because a treatment is available if they get sick.

“We have antivirals for shingles, but people don’t use that as a reason to refuse the shingles vaccine,” he said.

But other doctors say it’s hard to compare other infections with the coronavirus, given how politically charged COVID has become. Some vaccine opponents believe the dangers of the coronavirus have been exaggerated or that drug firms are suppressing less profitable treatments.


That’s the perspective of an unvaccinated retiree in his 80s who once ran a jewelry business in Attleboro. He asked not to be identified by name for fear of becoming the target of hostile reactions.

A self-described conservative who voted for Donald Trump to be president twice, he hasn’t gotten a COVID shot because he believes no safe and effective vaccine could have been created and authorized in roughly a year, as the Pfizer, Moderna, and Johnson & Johnson vaccines were.

He’s also unenthusiastic about antiviral drugs. He said there are safer and more affordable treatments, citing ivermectin, a controversial medicine to treat parasitic worms in people and animals. It’s been touted as a potential COVID treatment, even though the FDA and health experts say it is neither safe nor effective.

“Until I get information that shows me that it’s more effective or at least as effective as the stuff that existed already, I won’t” take antiviral drugs, the retiree said. “I don’t have love for big drug companies.”

Jonathan Saltzman can be reached at