US Measles Cases Highest Since 1996

Infections with measles virus have hit a 15-year high in the United States, says the Centers for Disease Control and Prevention. (Image: CDC/Cynthia S. Goldsmith; William Bellini, PhD)

Measles cases hit a 15-year high in the United States last year, due primarily to unvaccinated US residents who returned from overseas travel with the illness or to foreign visitors who came into the country while sick with measles.

The US Centers for Disease Control and Prevention (CDC) released the new figures today, along with a strong recommendation that parents make sure their children are properly immunized and that clinicians be able to diagnose measles and rapidly report cases to their local or state health departments.

“Measles is still a threat; it can be serious,” said Anne Schuchat, MD, director of the CDC’s Office of Infectious Diseases, during a press briefing today. Measles complications include pneumonia and encephalitis, which can be fatal. The last reported measles death in the United States was in 2008.

The new data, which will appear in tomorrow’s Morbidity and Mortality Weekly Report, show that 222 measles cases and 17 outbreaks were reported in 2011. From 2001 to 2010, a median of 60 cases and 4 outbreaks were reported annually. Half of the 2011 cases were linked with outbreaks, which the CDC defines as 3 or more related cases. Ninety percent of the cases were linked with measles virus infection contracted outside the United States.

Some 86% of the infections were in people who weren’t vaccinated against the infection or didn’t know if they had been vaccinated. Among them were 66 patients aged 16 months to 19 years who Schuchat said should have received vaccine reminders from clinicians or schools. Of those 66, 50 weren’t vaccinated because of philosophic, religious, or personal objections.

Schuchat said states in the Northwest have been “hot spots” for vaccination exemptions. She said parents sometimes find it easier to sign a school exemption form than to have their children immunized, or they don’t think measles is a threat anymore. Exemptions have declined in Washington State but increased in other states, she added.

Because measles was eliminated 12 years ago in the United States, Schuchat said many clinicians either don’t know or don’t remember what measles looks like. But rapid diagnosis and reporting is important to prevent outbreaks or keep them from spreading.

The CDC report showed that 72 of the 222 measles infections were directly acquired in another country. Almost half of those infections occurred in countries in the World Health Organization’s European Region. Schuchat said the European countries hardest hit by measles are France, Italy, and Spain—places where US residents travel frequently.

She advised those traveling to the 2012 Summer Olympics in London to “bring back memories, not measles.”

Categories: Immunization, Infectious Diseases, Public Health, Travel Medicine, Viral Infections