Antibody levels keep measles at bay in US

NEW YORK (Reuters Health) - Nearly 96 percent of people in the United States have antibodies against measles, a level high enough to sustain the elimination of the disease, which was eradicated in 2000, according to an analysis of data from 1999 to 2004.

However, some subpopulations in the U.S. might be at increased risk if the virus is reintroduced.

Dr. Geraldine M. McQuillan of the Centers for Disease Control and Prevention in Atlanta, and colleagues measured measles antibody levels in 16,049 individuals between 6 and 49 years old who were participants in the National Health and Nutrition Examination Survey (NHANES).

Antibodies are immune system proteins that fight off foreign bodies, such as viruses, bacteria and allergens. Therefore, the detection of antibodies in the blood means that the individual has previously been exposed to the pathogen.

As noted, measles antibodies were detected in almost 96 percent of subjects. Non-Hispanic black race, more than a high school education, health insurance, and birth outside the United States were factors that made the detection of measles antibodies more likely.

Non-Hispanic whites and Mexican Americans born between 1967 and 1976 had "significantly lower" antibody levels than other groups and could be at risk if measles reappears in the population.

Dr. Walter A. Orenstein of Emory University in Atlanta and colleagues point out in an editorial that as long as measles virus circulates in the world, "it will remain essential that we maintain our fence and minimize its gaps and holes."

This will require careful surveillance to detect new cases and outbreaks and monitoring immunization coverage with "serosurveys" such as the one McQuillan and colleagues conducted.

SOURCE: The Journal of Infectious Diseases, November 15, 2007.

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