Mayor Bill de Blasio urged on Friday that New York City’s private businesses require their workers to get vaccinated against the coronavirus and signaled that he would introduce similar measures for hundreds of thousands of municipal employees.

The mayor’s comments came just days after he announced that all employees in the public hospital system would have to either receive a virus vaccine or submit to weekly testing.

The move reflected growing concern that New York, like much of the United States, is on the verge of another wave of the pandemic. In just a few weeks, case counts in the city have tripled, to more than 650 a day on average, while inoculation rates have leveled off.