New York City sets a sweeping vaccine mandate for all private employers.

Mayor Bill de Blasio announced a sweeping coronavirus vaccine mandate for all private employers in New York City on Monday morning to combat the spread of the Omicron variant.

Mr. de Blasio said the aggressive measure, which takes effect Dec. 27 and which he described as the first of its kind in the nation, was needed as a “pre-emptive strike” to stall another wave of coronavirus cases and help reduce transmission during the winter months and holiday gatherings.

“Omicron is here, and it looks like it’s very transmissible,” he said in an interview on MSNBC. “The timing is horrible with the winter months.”