US Measles Cases Reach 20-Year High

The number of measles cases reported to the Centers for Disease Control and Prevention during the first 5 months of 2014 is the highest reported for that period since 1994.

From January 1, 2014, to May 23, 2014, 288 cases of measles were reported in the United States, according to a report in the June 6, 2014, issue of the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report. This is the largest number of cases reported in 20 years, and almost all of them have been associated with international travel by unvaccinated people.

The Centers for Disease Control and Prevention evaluated measles cases reported by states and found that the number of cases reported for 2014 so far surpasses the highest reported yearly total of cases since measles elimination was declared in 2000. This is also the greatest number of cases that have been reported during the first 5 months of a year since 1994. Patients with measles have ranged in age from 2 weeks to 65 years and 52% were aged 20 years and older. Of the 288 patients, 43 (15%) were hospitalized and no deaths have been reported. Cases have been reported in 18 states and New York City, with most occurring in Ohio (138), California (60), and New York City (26).

Of cases this year, 97% were associated with importations from at least 18 countries. A total of 45 direct importations were reported, 49% of which were in patients returning from the Philippines. Other importations were associated with travel from countries belonging to the World Health Organization Western Pacific, South-East Asia, European, Americas, and Eastern Mediterranean regions.

The report also found that 15 outbreaks accounted for 79% of reported measles cases, including the largest outbreak reported in the country since elimination. The ongoing outbreak has been associated with 138 cases so far, occurring mostly among unvaccinated Amish communities in Ohio.

A majority of all cases (69%) occurred among unvaccinated patients and 20% were reported among patients with unknown vaccination status. Among unvaccinated patients who contracted measles, 85% refused vaccinations for religious, philosophical, or personal reasons.

Although measles elimination has been maintained and vaccine coverage is high, the report suggests that importations and outbreaks among unvaccinated communities still pose a threat.

“[C]overage varies at the local level, and unvaccinated children tend to cluster geographically, increasing the risk for outbreaks,” the report notes. “Thus, maintaining high measles vaccination coverage is critical to prevent large measles outbreaks in the United States.”

Health care professionals should remind patients traveling internationally about the increased risk for measles and encourage vaccination, the report suggests. The measles, mumps, and rubella (MMR) vaccine is recommended for all children, with the first dose given at age 12 to 15 months and a second dose at age 4 to 6 years. Children and adolescents who have not received 2 appropriately spaced doses are recommended to receive catch-up vaccination. Adults are recommended to receive at least 1 dose of the MMR vaccine, and health care personnel, college students, and international travelers should receive 2 appropriately spaced doses.