Pfizer said Tuesday that its experimental pill to treat Covid-19 appears effective against the omicron variant. 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.

Separate laboratory testing shows the drug retains its potency against the omicron variant, the company announced, as many experts had predicted. Pfizer tested the antiviral drug against a man-made version of a key protein that omicron uses to reproduce itself. The updates come as Covid-19 cases, deaths and hospitalization are all rising again and the U.S. hovers around 800,000 pandemic deaths. The latest surge, driven by the delta variant, is accelerating due to colder weather and more indoor gatherings, even as health officials brace for the impact of the emerging omicron mutant.