NEW YORK (AP) — Teachers and other school staff members were supposed to be vaccinated against COVID-19 when the bell rang Monday morning for New York City’s sprawling school system. Mayor Bill de Blasio warned that unvaccinated school staffers would not be allowed to work Monday. United Federation of Teachers president Michael Mulgrew said 97% of his union’s members had received at least one vaccine dose as of Monday morning. New York City’s schools are among the first in the nation to require all employees to be inoculated against the coronavirus. A similar mandate is set to go into effect in Los Angeles on Oct. 15.