FILE - This 2003 electron microscope image made available by the Centers for Disease Control and Prevention shows mature, oval-shaped monkeypox virions, left, and spherical immature virions, right, obtained from a sample of human skin associated with the 2003 prairie dog outbreak. U.S. health officials are expanding the group of people recommended to get vaccinated against the monkeypox virus. They also say they are providing more monkeypox vaccine, working to expand testing, and taking other steps to try to get ahead of the outbreak. (Cynthia S. Goldsmith, Russell Regner/CDC via AP, file)
NEW YORK — Reacting to a surprising and growing monkeypox outbreak, U.S. health officials on Tuesday expanded the group of people recommended to get vaccinated against the monkeypox virus.