Courtesy: Marcio Jose Sanchez/AP (CNN) — With the highly contagious Delta variant spreading, particularly among unvaccinated Americans, it may be time for much of the country to put masks back on, experts said. "We are at a very different point in the pandemic than we were a month ago," Dr. Leana Wen told CNN on Tuesday. "And, therefore, we should follow the example of LA County and say that if there are places where vaccinated and unvaccinated people are mixing, then indoor mask mandates should still apply." Los Angeles County reinstated a mask mandate over the weekend, requiring masking indoors regardless of vaccination status.