In July, the CDC announced that the measles made a comeback. It was reported that at least 127 people in 15 states had come down with the infection - the biggest outbreak in the United States in more than 10 years. Cases started springing up in May, when more than 70 people in a dozen states became ill. According to federal health officials, most of the victims were not vaccinated against the highly contagious virus. In a statement, the CDC said the outbreak was traced to travelers who became sick overseas, returned to the United States and infected others.