Biden also has no more sway than Trump over a mutating virus that scientists have only begun to understand. The Washington Post’s rolling seven-day national average of coronavirus cases is more than 65,000 new cases per day, an 19 percent uptick since the middle of last month, even as many states drop public health restrictions and new variants spread. More than 146,000 new cases were reported on Thursday and Friday, the highest two-day count in several weeks, according to state data tracked by The Post. The B.1.1.7 variant first identified in the United Kingdom, which has been shown to be more contagious and lethal than the original “wild” virus, is now the most common lineage in the United States, administration officials said Wednesday. After three coronavirus surges under Trump, most experts say a “fourth wave” is unlikely given the accelerating pace of vaccinations and the number of Americans who have acquired natural immunity after being infected by the virus. But the trends have alarmed some public health experts, who are calling on Biden to adopt strategies to speed up shots or take a harder line with states relaxing restrictions. On Tuesday, the president announced he was moving up the deadline for all adults to be eligible for vaccines to April 19, although that doesn’t guarantee they will be able to be inoculated right away... “It’s all tied in people’s minds to what I call the key policy measure: ‘Next Thanksgiving, can I eat with my family in person?’” Blendon said, adding Americans would blame Biden if virus-related shutdowns are needed again. “They can’t blame a variant.”