NEW YORK (AP) — New York Mayor Bill de Blasio says all private employers big and small in the city will have to require their workers to get vaccinated against COVID-19 by Dec. 27. It is the most sweeping vaccine mandate of any state or big city in the U.S. De Blasio said Monday that the move is aimed at preventing a spike in coronavirus infections during the holiday season and the colder months. He called it a “preemptive strike.” Also, anyone 12 or older who wants to dine indoors at a restaurant, go to a gym or see a show will have to produce proof of having received two shots of the vaccine, up from the current one dose. And children ages 5 to 11 will have to show proof of at least one shot. The mayor said he expects the new mandate to survive any legal challenges.