Pfizer Says Its Covid Antiviral Pill Is Effective Against Omicron Variant

Topline

Pfizer released three separate laboratory studies Tuesday showing its antiviral drug Paxlovid is effective at treating the omicron variant of the coronavirus, amid uncertainty over whether some other common Covid-19 treatments work against the heavily mutated new variant.

(Photo Illustration by Jakub Porzycki/NurPhoto via Getty Images)

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Key Facts

One of the lab studies found nirmatrelvir – a key ingredient in Paxlovid–was effective at staving off an enzyme that the coronavirus needs to replicate in both the omicron variant and the virus’ original variant, Pfizer said in a press release.

In another study, the drug showed similar antiviral activity against omicron and several previous variants of the coronavirus, the statement said.

A third study conducted jointly by Pfizer and New York’s Icahn School of Medicine at Mount Sinai found that similar quantities of Paxlovid were needed to be effective against omicron and other previous variants, the statement said.

Last month, Pfizer said clinical trials showed Paxlovid is 89% effective at preventing hospitalization or death among high-risk Covid-19 patients.

The U.S. government has ordered 20 million treatment courses of Paxlovid, all of which are expected to be delivered this year.

Big Number

99.5%. That’s the percentage of last week’s U.S. Covid-19 cases caused by omicron, the Centers for Disease Control and Prevention estimates. The delta variant makes up the rest of the cases.

Key Background

Last month, the Food and Drug Administration gave Paxlovid emergency use authorization for high-risk Covid-19 patients. Dr. Anthony Fauci has said antiviral drugs such as Paxlovid and molnupiravir, a treatment manufactured by Merck, will help put an end to the pandemic as the country continues to grapple with an omicron-driven wave of infections. Some other treatments have struggled against the omicron variant, including monoclonal antibody therapies by Regeneron and Eli Lilly. The Department of Health and Human Services temporarily paused distribution of those two treatments for more than a week last month, before resuming shipments to states on the grounds that they’re still effective against the delta variant.

Contra

Many health experts say vaccination remains the best way to prevent the spread of Covid-19 and lower the chances of hospitalization and death. Fauci said during a White House news briefing last week that although “virtually everyone is going to wind up” testing positive for the virus eventually, the chances of “getting sick are very, very low” for people who are vaccinated.

Tangent

Supplies of Paxlovid and other oral Covid-19 treatments are running low in hospitals in some states, including Michigan, New York, Ohio and Rhode Island. CNN reported last week around 160,000 courses of Paxlovid have been distributed, far too little to handle a recent jump in Covid-related hospitalizations. An average of 20,808 Americans were hospitalized for Covid-19 every day last week, up 4.2% from the previous seven- day period, according to the CDC.