The total number of reported coronavirus cases in the United States marched toward 50 million Monday, even as New York City imposed a vaccine mandate for all private employers, federal health authorities warned against travel to several European countries and more nations tightened restrictions on the unvaccinated.

The omicron variant of the virus, which is possibly more contagious than the widespread delta variant, had been found in 17 U.S. states as of Monday — just five days after the first case in the country emerged in California. That number reflected the potentially heightened transmissibility of the newest strain and an improved system for detecting it.

The latest turn in the two-year-old pandemic also brought echoes of its early stages as authorities reported that at least 17 passengers and crew from a cruise ship that docked in New Orleans over the weekend had been infected with the virus that causes covid-19.

The infected people aboard the Norwegian Breakaway cruise ship, operated by Norwegian Cruise Lines, were described as “asymptomatic” and sent home to self-isolate. The ship set sail from the same location Nov. 28 with all 3,200 people aboard required to show proof of vaccination.... Read More: Washington Post