Elimination of measles in the Americas.

Of the 5551 confirmed measles cases reported in 1995 in the Americas, 2301 (41%) occurred in Canada. In this issue (see pages 1407 to 1413) Drs. Penny A. Sutcliffe and Elizabeth Rea describe a measles outbreak that occurred during that year in a highly vaccinated secondary school population in Toronto. Their findings support the use of a two-dose measles vaccination strategy. In this editorial the author explains how a two-dose strategy lowers the incidence of primary and secondary vaccine failures and thus reduces the number of susceptible people to below the outbreak threshold. Two-dose programs in Finland, Sweden and the United States have dramatically reduced the incidence rates of measles in those countries, and it is expected that the implementation of two-dose programs and "catch-up" campaigns in Canada and the remaining countries of the Americas will eliminate measles from the Western Hemisphere by the year 2000.