Anxiety in the United States over COVID-19 is at its highest level since last winter, a new poll shows, as the delta variant rages, more states and school districts adopt mask and vaccination requirements and the nation’s hospitals once again fill to capacity.  The poll from The Associated Press-NORC Center for Public Affairs Research also finds that majorities of American adults want vaccination mandates for those attending movies, sports, concerts and other crowded events; those traveling by airplane; and workers in hospitals, restaurants, stores and government offices.  The poll shows that 41% are “extremely” or “very” worried about themselves or their family becoming infected with the virus. That is up from 21% in June, and about the same as in January, during the country's last major surge, when 43% were extremely or very worried.