Pfizer’s COVID-19 antiviral proves almost 90% effective in latest trial data, as U.S. passes 50 million confirmed cases of the illness

Pfizer Inc. cheered investors Tuesday with final data from a late-stage trial of its COVID-19 antiviral, that found it reduced the risk of hospitalization or death in high-risk adults by 89% if given shortly after the onset of symptoms, confirming the first set of data released last month.