The U.S. reported nearly half a million new COVID infections in a single day, marking the largest daily total of any country during the pandemic. More than 486,000 new cases were reported in a 24-hour period, the Centers for Disease Control and Prevention said Thursday. Fifteen states reported a record-high number of average daily infections: Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Virginia and Washington. Puerto Rico and Washington, D.C., are also averaging more daily cases than ever. With COVID-19 cases rising so fast, fueled by the rapid spread of the Omicron variant, it's estimated that more than three Americans are testing positive every second, according to CDC data. In New York, cases are up 11% since Wednesday. Hospitalizations are at their highest level since September, with more than 81,000 COVID patients hospitalized nationwide, according to the CDC. A CDC model suggests more than 42,000 Americans could die in the next three weeks. "We are at the very beginning, unfortunately, and likely have at least four to eight weeks before we're going to see it rise and then begin to fall again. And during that time, we are going to see COVID activity in this country like we haven't seen since the beginning of the pandemic," Michael Osterholm, an epidemiologist at the University of Minnesota, told CBS News. "We're not going to live forever in a constant crisis, but for the time being, it's going to be a challenge," Osterholm added.