Hospital-Associated Measles Outbreak—Pennsylvania, March—April 2009

Although endemic measles transmission has been interrupted in the US, importations of this highly infectious virus continue. On March 28, 2009, a physician notified the Pennsylvania Department of Health (PADOH) of a measles case involving an unvaccinated child. Within 5 days, four additional cases were reported to PADOH and the Allegheny County Health Department. All five infected persons had been in the same hospital emergency department (ED) on March 10; one of them was a physician who worked in the ED. Here, Green et al highlight the potential for measles transmission in health-care settings. "A CDC editorial note is included."