In 2014 the United States had a record number of measles cases: 644 cases in 27 states, according to the Centers for Disease Control.
It was by far the most cases “since measles elimination was documented in the U.S. in 2000,” according to the CDC. Measles is endemic in some other countries, and people can bring it here by traveling. It is extremely contagious, and can lead to deadly pneumonia, ear infections, and deafness.
Between 2000 and 2013, cases stayed around 100 or 200 across the country, but, like 2014, this year is off to a fast start, and most of those who became ill were unvaccinated.
From Jan. 1 to Jan. 23, 2015, 68 people from 11 states were reported to have measles, according to the CDC. Most of those measles cases are part of an outbreak linked to Disneyland in California.