The Centers for Disease Control and Prevention (CDC) has issued a report on preventable measles in the United States. The report, “Preventable Measles Among U.S. Residents, 2001–2004,” was published in the August 26, 2005, issue of Morbidity and Mortality Weekly Report and is available online at http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5433a1.htm.

Although measles has been eliminated in the United States, the disease continues to be imported from other areas of the world where it is still endemic. This results in substantial morbidity and expenditure of local, state, and federal public health resources. Measles is brought into the United States by returning residents who become infected while living or traveling abroad, from contact or association with an infected traveler, or from an unknown source. Most cases of measles in the United States can be prevented by following recommendations for vaccination, including specific guidelines for travelers.

There were 251 cases of measles reported to the CDC between 2001 and 2004; 177 (71 percent) occurred among U.S. residents and 74 (29 percent) occurred among nonresidents. Of the cases among U.S. residents, 100 (56 percent) were preventable and 77 (44 percent) were not preventable.

Confirmed cases of measles that occurred among persons for whom vaccination is recommended by the Advisory Committee on Immunization Practices but who have not received one or more doses of measles-containing vaccine (MCV) were defined as preventable. Of the 100 preventable cases, 43 occurred among international travelers and 57 occurred among nontravelers. There were 17 preventable cases among travelers six to 15 months of age, 12 of which occurred among infants six to 11 months of age and five of which occurred among children 12 to 15 months of age. Among persons older than 16 months, there were 83 preventable cases; 26 were in persons who became infected during international travel and 57 were in persons infected in the United States.

Cases that occurred among persons who: (1) had received one or more doses of MCV; (2) were not vaccinated and for whom vaccination is not recommended; and (3) were born before 1957 were defined as nonpreventable. Twelve (16 percent) of the 77 nonpreventable cases occurred among international travelers; 11 had received at least one dose of MCV and the other had been born before 1957. There were 65 cases (84 percent) of nonpreventable measles reported among nontravelers.

Three or more epidemiologically linked cases of measles were defined as an outbreak. There were 14 outbreaks of measles identified between 2001 and 2004. Nine of the outbreaks involved three or more U.S. residents, seven of which originated with a U.S. resident traveler. One outbreak occurred in 10 patients in a day care center who were exposed to an unvaccinated nine-month-old day care attendee who was infected during travel abroad.