The measles outbreak spread to three more states and Washington D.C. last week, affecting 19 additional people, according to an update posted Monday by the Centers for Disease Control and Prevention. The highly contagious disease is now in 18 jurisdictions, with 121 people affected. The vast majority of the cases are part of the large outbreak that began in Southern California Disney theme parks in late December, the health agency said. Public health authorities have begun campaigning about the importance of vaccinating children against measles. President Obama, Surgeon General Vivek H. Murthy and Baltimore Public Health Commissioner Leana S. Wen, as well as the CDC and other public health organizations have called on parents to vaccinate children.