All private employers in New York City will have to require their workers to get vaccinated against COVID-19, the mayor announced Monday, imposing one of the most aggressive vaccine rules in the nation. The move by Mayor Bill de Blasio comes as cases are climbing again in the U.S. and the worrisome omicron variant is gaining a toehold in New York and elsewhere around the country. “We in New York City have decided to use a preemptive strike to really do something bold to stop the further growth of COVID and the dangers it’s causing to all of us,” he said. De Blasio, a Democrat with just weeks left in office as leader of the nation’s largest city, said the mandate will take effect Dec. 27, reports AP. Speaking on MSNBC’s “Morning Joe,” he said the move is aimed at staving off a spike of infections amid holiday gatherings and as cold weather drives more people indoors, where the virus is more likely to spread. Vaccine mandates across states and cities vary widely, with some states resisting any mandates and others requiring the shots for government employees or certain sectors that run a particularly high risk, such as health care workers. But most officials have not announced mandates reaching as far into the private sector, nor mandates covering so many people. — Agencies