Covid-19 infections continued to soar far above previous peaks across the U.S., as students returned to classrooms while some workers remained home after contracting or being exposed to the virus.

The seven-day average of daily reported Covid-19 cases in the U.S. reached a pandemic record 403,385 on Sunday, according to a Wall Street Journal analysis of Johns Hopkins University data. The fresh peak arrived even as most states paused reporting during the New Year’s holiday weekend. Reporting delays will likely lead to spikes in reports of cases this week as states catch up. While Covid-19 tests remain in short supply in much of the U.S., Covid-19 testing was less robust last year, complicating comparisons between pandemic surges.