Progress toward measles elimination--region of the Americas, 2002-2003.

In 1994, countries in the Region of the Americas adopted the goal of eliminating endemic measles transmission in the Western hemisphere by 2000. Since 1994, rapid progress has been made. The number of measles cases has declined >99%, from approximately 250,000 in 1990 to 105 confirmed cases reported in six countries in 2003. During 2003, only Mexico and the United States reported outbreaks. The three chains of transmission in Mexico and two U.S. outbreaks were import-related; a third U.S. outbreak was of unknown source. Since November 2002, no transmission of the D6 and D9 genotypes has been reported; these genotypes were responsible for several large outbreaks in the region during 1997-2002. This report summarizes the epidemiology of measles in the Americas during 2002-2003 and highlights progress toward measles elimination, including the lowest ever number of reported measles cases in the region. Because the region is under constant threat of measles importation from regions where the disease is endemic, countries must maintain high population immunity to measles and sensitive surveillance to ensure the timely detection of imported cases and allow for rapid implementation of control measures.