CHICAGO (AP) — Chicago Mayor Lori Lightfoot says the nation’s third-largest city will require proof of coronavirus vaccination at restaurants, bars, gyms and other indoor venues. Lightfoot said Tuesday that the requirement will take effect Jan. 3. It comes as the rapidly spreading omicron variant has led to a spike in COVID-19 infections. Lightfoot says she hasn’t been as concerned about COVID-19 as she is now since the early days of the pandemic in 2020. On Monday, Illinois reported about 12,330 new COVID-19 cases, which is the highest daily total in more than a year. Chicago is seeing an average of 1,700 cases per day, up from about 300 per day just weeks ago. Much of that increase has been driven by the omicron variant, prompting fears of a winter surge.