International measles importations United States, 1980-1985.

Between 1980 and 1985, 89-121 international measles importations were reported annually in the US, accounting for 0.7-6.9% of the annual number of reported measles cases. These measles cases were acquired in more than 70 different countries. Three countries accounted for over one third of all imported cases: Mexico, the UK and the Philippines. Thirty-six states reported importations. However, over half of all importations were reported from only six states: California, New York, Maryland, Florida, Texas and Hawaii. Most measles importations did not cause transmission in the US. In 1982 and 1985 only 16% and 29% of importations resulted in any spread cases. Until there is better control of measles worldwide, high immunization levels are crucial for continued measles control in the US.