When flu epidemics loom, the long-standing recommendation of the U.S. Centers for Disease Control and Prevention is to vaccinate the elderly first, because they are at greater risk of dying if they contract the virus. New evidence suggests that youngsters should take priority. Work at Yale University and Rutgers University underlines that children are the group most responsible for spreading the flu: they carry the virus into the home and infect adults, who then bring the flu into the workplace. Vaccinating most young people would virtually eliminate the flu, the researchers calculate, thereby cutting down on the mortality of the elderly, the young and people overall. The details are in the March 27 Proceedings of the National Academy of Sciences USA.