The United States reported nearly 1 million new coronavirus infections on Monday, the highest daily tally of any country in the world and nearly double the previous US peak set a week ago as the spread of the Omicron variant showed no signs of slowing.

The number of hospitalized Covid-19 patients has risen nearly 50 percent in the past week and now exceeds 100,000, according to data collected by Reuters, marking the first time that threshold has been reached in a year.

The latest surge, which forced waves of cancellations from commercial airlines flights to...