Philadelphia has reinstated a face-mask mandate for students and teachers that comes into effect Monday, in its latest move to rein in COVID-19 infections. The news was announced Friday by Dr. William Hite, superintendent for the school district, who said it would remain in effect until further notice. "As we've learned since the pandemic began, the coronavirus continues to evolve and so too will our response to it," Hite said in a statement. COVID cases continue to rise across the U.S. and trend at the highest levels seen since March, driven by the BA.2 variant of omicron, and two other subvariants that appear to be even more infectious. The U.S. is averaging 108,065 cases a day, up 53% from two weeks ago, according to a New York Times tracker. The country is averaging 24,728 hospitalizations a day, up 30% from two weeks ago. The daily death toll has fallen to 309 on average, down 16% from two weeks ago. Cases are higher in nearly every state, but the Northeast and Midwest are being particularly hard hit with case reports in both regions now higher than they were at the peak of last summer's delta surge. There are concerns that case numbers are even higher, as many people are now testing at home and the data is not being collected. On a global basis, total cases are now above 525.6 million. Total deaths are above 6.27 million, according to data aggregated by Johns Hopkins University , with the U.S. still leading the way with 83.3 million cases and 1,002,173 deaths.