U.S. health regulators on Wednesday authorized the first pill against COVID-19, a Pfizer drug that Americans will be able to take at home to head off the worst effects of the virus. The oral drug, Paxlovid, is a faster, cheaper way to treat early COVID-19 infections, though initial supplies will be extremely limited. All of the previously authorized drugs against the disease require an IV or an injection. An antiviral pill from Merck also is expected to soon win authorization. But Pfizer's drug is all but certain to be the preferred option because of its mild side effects and superior...