Some 539 US measles cases were reported between January 1 and June 27, making 2014’s case total to date the country’s highest since elimination of the infection in the United States was documented in 2000. This figure also represents the highest number of cases during the first 5 months of the year since 1994. The Centers for Disease Control and Prevention (CDC) has emphasized that clinicians need a heightened awareness of measles in their communities and the importance of vaccination.
Measles cases were reported in 20 states throughout the country, including Hawaii, according to the CDC. The 17 outbreaks that have occurred represent 88% of cases reported in the first 6 months of this year. The majority of US residents who have contracted measles haven’t been vaccinated. In Ohio, for example, an outbreak involving at least 138 cases cropped up in unvaccinated Amish communities (http://1.usa.gov/1jWpxkd).
Most of the cases reported this year have been in foreign visitors or US residents returning from travel abroad. Some had been infected in the Philippines, where about 40 000 measles cases and 70 measles deaths had been reported this year between January 1 and May 20. The outbreak in the Philippines has been ongoing since October 2013. Measles remains endemic in 5 of the 6 World Health Organization regions of the world; about 20 million cases are reported globally each year.
The CDC has advised clinicians to ask patients with clinical measles symptoms—fever, rash, cough, inflamed nasal tissues, and conjunctivitis—whether they’ve traveled abroad recently or been in contact with others who have been out of the country. Because measles has been misdiagnosed as Kawasaki disease, dengue, scarlet fever, and other conditions, clinicians should consider measles when diagnosing cases of illness with signs and symptoms that are compatible with measles.
High vaccination rates among young children have helped prevent imported measles cases from spreading. However, the CDC noted that unvaccinated children tend to cluster geographically, increasing the risk for outbreaks. Maintaining high immunization levels is a critical part of preventing large outbreaks as well as protecting infants too young for vaccination and others who have medical conditions that make vaccination inadvisable.