The United States has passed 15 million confirmed coronavirus cases, according to data from Johns Hopkins University. Infections are skyrocketing around the country, and the U.S. hit 14 million cases on Dec. 3, just five days before Tuesday’s grim milestone. Despite the staggering figures, public health experts have warned that the worst is yet to come, with a surge in cases from Thanksgiving gatherings just now beginning to register and another expected after Christmas. The U.S. has the most COVID-19 cases in the world as well as more than 280,000 deaths, also the highest globally, according to Johns Hopkins. The United Kingdom began mass vaccinations against the coronavirus Tuesday, and the U.S. Food and Drug Administration is poised to grant Pfizer’s vaccine emergency use authorization, though experts predict it will be several months before the general populace reaches the threshold for general immunity.