NEW YORK (NYTIMES) - Paxlovid, the Covid-19 treatment made by Pfizer, reduced hospitalisations and deaths in older patients during the Omicron surge in Israel earlier this year, but made no difference for patients younger than 65 at high risk for severe disease, new research has found.
The study is one of the first published examinations of the real-life effectiveness of Paxlovid against the Omicron variant, now the dominant version of the coronavirus.
Pfizer's trials of Paxlovid were conducted during a surge of the Delta variant last year, and included only unvaccinated individuals.
There have been lingering questions about how effective the medication is against the Omicron variant, and among patients who are vaccinated or have some immunity from a prior bout of Covid-19. The drug has been available to Americans since December.
The new study did not address another pressing mystery: how often patients experience "rebound" cases of Covid-19 after taking the drug.
Jill Biden, the first lady, exited a second isolation period Monday (Aug 30) after her infection returned following a course of Paxlovid.
On Friday, Dr Ashish Jha, the White House Covid-19 response coordinator, said on Twitter that while there was confusion over who should take Paxlovid, the data still indicated that it should be administered to anyone age 50 and older soon after they develop Covid-19 symptoms, as well as to anyone with health conditions leaving them vulnerable to severe illness.
Although the Israeli study found that the drug had no benefit for adults ages 40-64 with underlying health problems, other research has suggested that it can improve outcomes.
Researchers at Massachusetts General Brigham health system reported that Paxlovid significantly reduced hospitalisations among patients ages 50-64, with a pronounced effect among unvaccinated individuals and those with obesity.
Jha said on Twitter that there was no reason to think the drug's benefits would accrue only to older or more vulnerable populations. He noted that there were few side effects (the most notable is a metallic taste in the mouth), and that there was no shortage of Paxlovid in the United States.
Pfizer's own studies found that Paxlovid reduced the risk of hospitalisations and deaths by 88% in unvaccinated individuals at high risk for severe Covid-19, so long as the drug was taken within the first five days of symptom onset.