There’s another pill to treat COVID-19 that’s expected to be considered for federal approval after Pfizer announced Friday that its new antiviral drug is 89% effective in reducing hospitalizations and deaths from the virus in high-risk adults.

Pfizer, the company behind one of the three COVID-19 vaccines approved for use in the United States, said the clinical trial for the drug paxlovid will be stopped “due to the overwhelming efficacy demonstrated in these results.” The company said it is seeking emergency use authorization from the U.S. Food and Drug Administration.

Last month, Merck and Florida-based Ridgeback Biotherapeutics submitted a similar request for their drug, molnupiravir, after finding it cut the risk of hospitalization or death from COVID-19 by about 50% in adults seen as likely to progress to severe illness because they’re older or have certain medical conditions, such as heart disease.

The United Kingdom became the first country to approve the use of the Merck pill Thursday.

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The pills, the first medication for COVID-19 patients that can be taken orally rather than being injected or given intravenously, like monoclonal antibody treatments, are being called a game changer for a pandemic now in its second year.

But Dr. Brandon Webb, an Intermountain Healthcare infectious diseases physician, said while the new antiviral treatments are “good news,” the pills should not be seen as a substitute for getting vaccinated against the virus and taking other preventive measures such as wearing a mask.

“Treatments should be looked at as a safety net or a Band-Aid for individuals who unfortunately do get COVID,” Webb said. “But they’re not a solution to the pandemic.”

Still to come, the doctor said, is detailed data about how safe the pills are to take, and how well they’re tolerated by patients. The Pfizer pill series includes a protease inhibitor, part of the drug “cocktail” treatment for HIV patients that’s been in use for many years.

“There will be some really important real-world practicalities,” he said. “From having treated patients with HIV with protease inhibitors, we know that those are very commonly associated with nausea, vomiting and diarrhea, as well as a number of other drug interactions and other things we need to watch out for.”

The pills were initially studied in high-risk patients who had not gotten vaccinated, Webb said, the group most likely to see the biggest benefit. At least initially, the pills are expected to be authorized only for adults considered at high risk of hospitalization or death from COVID-19, and administered under a doctor’s care, he said.

“Before we crown it a game changer, I think it’s important to recognize that these oral drugs may not be for everyone. Not everyone will tolerate them,” Webb said, and some may be taking other drugs for medical conditions that could cause issues.

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“All drugs have side effects and all drugs have a risk versus benefit profile,” he said, adding that it’s important for people to understand that “right now, we don’t know that the safety of the pills is any better than the safety of the vaccines.”

Concerns have been raised about treatments being viewed as an alternative to vaccination, considered the key to stopping the spread of the deadly virus, Webb said. In Florida and other states, people have skipped vaccines and other cheaper methods of preventing COVID-19 in favor of monoclonal antibody treatments that cost $2,100.

“There’s always a concern in the current political environment that the role of treatments for COVID will be misinterpreted as a primary therapy rather than a secondary therapy that is intended to complement preventive measures and vaccinations,” Webb said.

Only developing immunity to the virus through widespread vaccination can prevent the emergence of new variants — like the delta variant that drove up case counts, hospitalizations and deaths starting last summer — and stop the pandemic, the doctor said.

Pfizer Chairman and Chief Executive Officer Albert Bourla touted the pills in a news release as having “the potential to save patients’ lives, reduce the severity of COVID-19 infections, and eliminate up to nine out of 10 hospitalizations.”

Bourla called the news of the clinical trial results “a real game changer in the global efforts to halt the devastation of this pandemic.”

A Pfizer executive who led the drug’s development, Annaliesa Anderson, said, “The results are really beyond our wildest dreams,” the New York Times reported. She said he hopes the new drug “can have a big impact on helping all our lives go back to normal again and seeing the end of the pandemic.”