Pfizer says its COVID-19 treatment pill works against the Omicron variant

Pink and white pills
Pfizer says its COVID-19 treatment pill appears to be effective against the Omicron variant.

Pfizer said Tuesday that its experimental COVID-19 pill appears to be effective against the Omicron variant of the coronavirus.

The company also said full results of its 2,250-person study confirmed the pill’s promising early results against the virus: The drug reduced combined hospitalizations and deaths by about 89% among high-risk adults when taken shortly after initial COVID-19 symptoms.

The company said separate laboratory testing showed that the drug retained its potency against the Omicron variant, as many experts had predicted. Pfizer tested the antiviral drug against a man-made version of a key protein that the Omicron variant uses to reproduce itself.


Both the Pfizer pill and a rival one from Merck are expected to perform well against Omicron because they do not rely on attacking the coronavirus’ spike protein, which contains most of the new variant’s mutations.

Pfizer’s experimental updates come as COVID-19 cases, deaths and hospitalizations are all rising again and the U.S. hovers around 800,000 pandemic deaths. The surge driven by the Delta variant is accelerating because of colder weather and more indoor gatherings, even as health officials brace for the effect of the emerging Omicron strain.

The Food and Drug Administration is expected to rule soon on whether to authorize Pfizer’s pill and Merck’s drug, which was submitted to regulators several weeks earlier. If granted, the pills would be the first COVID-19 treatments that Americans could pick up at a pharmacy and take at home.

An analysis finds Pfizer’s COVID-19 shots provide low protection against infection by the Omicron variant but high protection against hospitalization.

Dec. 14, 2021

Pfizer’s data could help reassure regulators of its drug’s benefit after Merck disclosed smaller-than-expected benefits for its drug in final testing. Late last month, Merck said that its pill reduced hospitalizations and deaths by 30% in high-risk adults.

Both companies initially studied their drugs in unvaccinated adults who face the gravest risks from COVID-19, because of older age or health problems such as asthma or obesity.

Pfizer is also studying its pill in lower-risk adults — including a subset who are vaccinated — and reported mixed data for that group Tuesday.

In interim results, Pfizer said its drug failed to meet its main study goal: sustained relief from COVID-19 for four days during or after treatment, as reported by patients. But the drug did achieve a second goal by reducing hospitalizations by about 70% among that group, which included otherwise healthy unvaccinated adults and vaccinated adults with one or more health issues. Fewer than 1% of patients who got the drug were hospitalized, compared with 2.4% of patients who got a dummy pill.


Pfizer has signed a deal allowing other manufacturers to make its COVID-19 pill, which is awaiting a green light from U.S. regulators.

Nov. 16, 2021

An independent board of medical experts reviewed the data and recommended that Pfizer continue the study to get the full results before proceeding further with regulators.

Across both of Pfizer’s studies, adults taking the company’s drug had a 10-fold decrease in coronavirus levels compared with those on a placebo.

The prospect of new pills to fight COVID-19 can’t come soon enough for communities in the Northeast and Midwest, where many hospitals are once again being overloaded by COVID-19 cases.

Centers for Disease Control and Prevention Director Rochelle Walensky, appearing on NBC’s “Today” on Tuesday, said the best way for people to protect themselves against COVID-19 is to get vaccinated and get a booster shot. She said the Pfizer pill, if authorized by the FDA, “will be another great tool, but we need to diagnose people early.”

The U.S. government has agreed to purchase enough of Pfizer’s drug to treat 10 million people and enough of Merck’s to treat 3 million, pending FDA authorization.