As cases tumble and states reopen, the potential final stage in the U.S. campaign to vanquish COVID-19 is turning into a slog, with a worrisome variant gaining a bigger foothold and lotteries and other prizes failing to persuade some Americans to get vaccinated. âThe last half, the last mile, the last quarter-mile always requires more effort,â Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention, said Wednesday. While two of the states slammed hardest by the disaster, California and New York, celebrated their reopenings this week with fireworks and a multimillion-dollar drawing, hospitalizations in parts of Missouri are surging and cases are rising sharply in Texas, illustrating the challenges the country faces this summer.