Measles

Abstract

In the pre-vaccine era, there were approximately 30 million measles infections and over one million measles-related deaths each year, worldwide. The live attenuated measles vaccine, developed in the 1960s, is safe and effective in the prevention of measles infection and its complications. In the United States, routine administration of the measles vaccine led to a rapid and dramatic decline in infections; however, measles outbreaks continue to occur, particularly in underimmunized communities. In 2014, two unvaccinated US residents from Knox County, Ohio, were hospitalized with a febrile respiratory illness and rash shortly after returning from the Philippines. They were diagnosed with dengue virus infection and treated with supportive care. It was not until a few weeks later, when multiple members of a local Amish community were diagnosed with measles, that a measles outbreak was identified, leading back to the diagnosis of measles in the returning travelers. This Amish community, one of the largest in the United States, had a single dose measles vaccination rate of 14%, much lower than that of the general population (over 88%). Over the next 4 months, 383 outbreak-related cases were identified, primarily in unvaccinated individuals within the Amish community. Despite the interaction between the Amish and the general population, the outbreaks were limited to the underimmunized Amish community, highlighting the importance of vaccination in disease prevention. A rapid public health response, including isolation of susceptible individuals and administration of measles vaccine to over 10,000 people, was effective in controlling the outbreak and preventing further spread of measles (Gastanaduy et al., N Engl J Med 375:1343–1354, 2016).