BACKGROUND: Although measles was eliminated in the United States in 2000, 
importations of the virus continue to cause outbreaks. We describe the 
epidemiologic features of an outbreak of measles that originated from two 
unvaccinated Amish men in whom measles was incubating at the time of their 
return to the United States from the Philippines and explore the effect of 
public health responses on limiting the spread of measles.
METHODS: We performed descriptive analyses of data on demographic 
characteristics, clinical and laboratory evaluations, and vaccination coverage.
RESULTS: From March 24, 2014, through July 23, 2014, a total of 383 
outbreak-related cases of measles were reported in nine counties in Ohio. The 
median age of case patients was 15 years (range, <1 to 53); a total of 178 of 
the case patients (46%) were female, and 340 (89%) were unvaccinated. 
Transmission took place primarily within households (68% of cases). The virus 
strain was genotype D9, which was circulating in the Philippines at the time of 
the reporting period. Measles-mumps-rubella (MMR) vaccination coverage with at 
least a single dose was estimated to be 14% in affected Amish households and 
more than 88% in the general (non-Amish) Ohio community. Containment efforts 
included isolation of case patients, quarantine of susceptible persons, and 
administration of the MMR vaccine to more than 10,000 persons. The spread of 
measles was limited almost exclusively to the Amish community (accounting for 
99% of case patients) and affected only approximately 1% of the estimated 32,630 
Amish persons in the settlement.
CONCLUSIONS: The key epidemiologic features of a measles outbreak in the Amish 
community in Ohio were transmission primarily within households, the small 
proportion of Amish people affected, and the large number of people in the Amish 
community who sought vaccination. As a result of targeted containment efforts, 
and high baseline coverage in the general community, there was limited spread 
beyond the Amish community. (Funded by the Ohio Department of Health and the 
Centers for Disease Control and Prevention.).