The United States logged 222 measles cases last year, well above the median of 60 cases a year that has been the norm during the last decade and the most cases since the 508 cases that occurred in 1996, the Centers for Disease Control and Prevention said Thursday. Most of the new cases were clustered in 17 outbreaks, about four times the normal number. All were the result of imported virus, either by U.S. citizens returning from vacations or by foreign visitors. About half of the cases originated in Western Europe.
The U.S. achieved measles elimination in 2000 as a result of widespread vaccination with the measles, mumps and rubella (MMR) vaccine. Elimination means that there were was no year-round endemic transmission of the virus. Nonetheless, cases occur because travelers can bring the virus into the country; the disease is still widespread outside North America. Worldwide, about 20 million people contract measles each year and an estimated 164,000 die from it. Most of those cases occur in developing countries, but the industrialized world is not exempt. Last year there were 37,000 measles cases reported in Europe, primarily in France, Italy and Spain. Susceptible people traveling to those countries thus have a distinct risk of contracting the disease.
Of the 2011 cases, according to a report in the CDC's Morbidity and Mortality Weekly Report, 141 were among people who were eligible for the MMR vaccine but, for one reason or another, did not receive it. Children under the age of 6 months are not eligible to receive it, as are those with leukemia and certain other severe diseases. People born before 1957 also do not typically receive the vaccine because it is assumed they were exposed to the virus before immunization programs began that year. Fifty of the patients had exemptions from receiving the vaccine. Until recent years, many parents sought exemptions because they feared -- without foundation -- that the vaccine is dangerous and could produce autism. More recently, according to Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Infectious Diseases, many harried parents simply sign the exemption application because that is easier than actually procuring the immunization. Many parents, she added, "simply don't think there is a threat of disease."
So far this year, she added, there have been an additional 25 cases.
While most people think of measles as relatively benign, that is not the case. It is extremely infectious and can be transmitted by coughs and sneezes, even before the typical rash appears. "You can catch it just by being in a room where a patient has been," Schuchat said. Even with the medical treatment available in the U.S., as many as three of every 1,000 people who contract it die. About a third of the 222 people who contracted measles in 2011 had to be hospitalized, although there were no fatalities.
The CDC recommends that all college students, healthcare personnel and anyone traveling outside the country have two doses of the MMR vaccine. All other adults should have at least one. Further information about guidelines for immunization is available here.