Diphtheria in the Russian Federation in the 1990s

A resurgence of diphtheria spread throughout the Russian Federation in the early 1990s; diphtheria had been well controlled, but circulation of toxige nic strains of Corynebacterium diphtheriae had persisted since the implemen tation of universal childhood vaccination in the late 1950s. More than 115, 000 cases and 3000 deaths were reported from 1990 to 1997, and, in contrast to the situation in the prevaccine era, most of the cases and deaths occur red among adults. Contributing factors included the accumulation of suscept ible individuals among both adults and children and probably the introducti on of new strains of C, diphtheriae. Vaccine quality, vaccine supply, or ac cess to vaccine providers did not significantly contribute to the epidemic. Mass vaccination of adults and improved childhood immunization controlled the epidemic. High levels of population immunity, especially among children , will be needed to prevent and control similar outbreaks in the future.