NEW YORK, April 26 (Xinhua) -- COVID-19 cases and hospitalizations are rising once again across the United States, driven by more contagious sub-variants of the virus and leaving health experts unsure whether vaccination and immunity from prior infection will be protective enough to prevent yet another deadly wave of infections, The Mercury News has reported.
Nearly a third of the country is now registering substantial or high levels of COVID transmission in the last seven days, including most Bay Area counties at the high level, The Mercury News reported on Sunday, citing the U.S. Centers for Disease Control and Prevention.
Death rates mostly have yet to increase, but in earlier waves, they tended to follow the trend in hospitalizations.
The rising numbers follow a relatively short reprieve from this winter’s nationwide surge propelled by the highly contagious Omicron variant. Omicron began spreading in December, with infections peaking a month later and then dropping sharply through February and March.
Nationally, average daily cases are up more than 70 percent since the end of March, though they remain far below the Omicron and Delta peaks, and the decline in hospitalization rates appears to be reversing, according to the report.
"The rebound comes just as U.S. officials dropped the mask mandate for public transportation after a judge in Florida said it exceeded their authority - with people from all over now crowding unmasked into planes, buses, subways and rail cars," it added.
原文地址：http://en.people.cn/n3/2022/0427/c90000-10089834.html