Pfizer says its oral COVID-19 pill could help prevent severe infection from the Omicron variant in high-risk people

• Pfizer's oral antiviral drug could help protect people at high risk of COVID-19 in trial, the company said.
• It cut the risk of hospitalization by 89%, when it was given within three days of symptom onset, Pfizer said.

Pfizer announced Tuesday that its oral antiviral pill could help protect those at high-risk of severe COVID-19.

Pfizer said in a press release that the drug, called Paxlovid, cut the risk of hospitalization or death by 89%, compared with a dummy drug, when given to people at high-risk of severe COVID-19 within three days of symptoms onset.

Adverse events were "comparable'" between the groups in the late stage trial of 2,246 people, Pfizer said.

Antiviral drugs won't replace vaccines but could be a vital tool for people who don't respond to them.

Albert Bourla, chief executive officer at Pfizer, said in a statement that "emerging variants of concern, like Omicron, have exacerbated the need for accessible treatment options for those who contract the virus." "We are confident that, if authorized or approved, this potential treatment could be a critical tool to help quell the pandemic," he said.

Everyone in the trial had at least one medical condition that put them at an increased risk of developing severe COVID-19. Participants were equally divided into two groups — participants in one group received Paxlovid and those in the other were given a dummy drug.

To get to the 89% figure, the study found five of 697 patients who received Paxlovid were hospitalized within 28 days, compared with 44 of 682 in the placebo group that received a dummy drug, Pfizer said. No-one died in the Paxlovid group and there were nine deaths in the placebo group, Pfizer said.

The latest findings were "consistent" with a preliminary analysis from November and have been shared with the Food and Drug Administration as part of an ongoing review, Pfizer said.

The study hasn't been published or scrutinized by other experts in a peer review.

Andrew Pekosz, vice chair of microbiology and immunology at the Johns Hopkins Bloomberg School of Public Health, told STAT, that the protection from hospitalization was "fantastic" and pointed to Paxlovid being a "really important weapon in our arsenal to fight COVID-19".

Celine Gounder, a clinical assistant professor of medicine and infectious diseases at the NYU Grossman School of Medicine and Bellevue Hospital, told STAT that the true indication of how much impact the drug will have on the disease will be determined by whether people can access it on time.

Eric Topol, director and founder of the Scripps Research Translational Institute, told STAT that his "big worry" was whether there would be enough supply of the drug.

Paxlovid hasn't been properly tested against the Omicron variant.

Most of the people in the trial caught the Delta variant — the most common variant worldwide. So it's not possible to tell from the trial exactly how effective it will be against COVID-19 caused by the new Omicron variant, which has 32 mutations in the part of the virus that infects human cells.

Annaliesa Anderson, senior vice president at Pfizer, told STAT that Pfizer had "great confidence" that Paxlovid will remain "potent" against Omicron, based on lab data showing the pill still stops an enzyme found in Omicron from working. Anderson said that the lab tests for Omicron hadn't been developed yet, per STAT.