Measles.

Measles, also known as rubeola, is a disease caused by the measles virus. Before routine measles vaccination began in 1963, nearly everyone got infected with measles during childhood. Once the measles vaccine became widespread, the number of measles cases dropped to fewer than 150 cases per year from 2001 to 2010. Since 2012, however, the number of U. S. as well as worldwide measles cases has increased dramatically. This is a major public health concern because of how easily the virus spreads and how serious the infection can be.