Imported measles cases associated with US outbreaks

Measles cases in the United States in 2011 were quadruple the usual number of cases during the previous decade, with almost all cases associated with importation.

During 2011, a total of 222 confirmed measles cases from 31 states and 17 measles outbreaks (defined as 3 or more cases linked in time or place) were reported to the Centers for Disease Control and Prevention. A median of 60 cases and 4 outbreaks were reported annually from 2001 to 2010.

Of the 222 cases, 112 (50%) were associated with 17 outbreaks. Ninety percent (n=200) were associated with importations from other countries, including 52 (26%) cases in US residents returning from abroad and 20 (10%) cases in foreign visitors.

Centers for Disease Control and Prevention. Measles-United States, 2011. MMWR Morb Mortal Wkly Rep. 2012;61:253-257.