Successful control of epidemic diphtheria in the states of the former Union of Soviet Socialist Republics: lessons learned.

Epidemic diphtheria reemerged in the Russian Federation in 1990 and spread to all Newly Independent States (NIS) and Baltic States by the end of 1994. Factors contributing to the epidemic included increased susceptibility of both children and adults, socioeconomic instability, population movement, deteriorating health infrastructure, initial shortages of vaccine, and delays in implementing control measures. In 1995, aggressive control strategies were implemented, and since then, all affected countries have reported decreases of diphtheria; however, continued efforts by national health authorities and international assistance are still needed. The legacy of this epidemic includes a reexamination of the global diphtheria control strategy, new laboratory techniques for diphtheria diagnosis and analysis, and a model for future public health emergencies in the successful collaboration of multiple international partners. The reemergence of diphtheria warns of an immediate threat of other epidemics in the NIS and Baltic States and a longer-term potential for the reemergence of vaccine-preventable diseases elsewhere. Continued investment in improved vaccines, control strategies, training, and laboratory techniques is needed. Background In the prevaccine era, diphtheria was a leading childhood killer worldwide. During the 1940s‐1950s, the introduction of universal childhood immunization with diphtheria toxoid nearly eliminated diphtheria in most industrialized countries. In developing countries, high levels of vaccination of infants with three doses of diphtheria-tetanus toxoids‐pertussis vaccine (DTP) have been achieved following implementation of the Expanded Program on Immunization of the World Health Organization (WHO) in the 1970s. A large proportion of adults in many developed countries and an increasing proportion of adults in some developing countries are now susceptible to diphtheria because vaccine-induced immunity wanes over time unless periodic boosters are given or unless exposure to toxigenic Corynebacterium diphtheriae occurs. In the 1980s and early 1990s, small outbreaks of diphtheria were reported in both industrialized (Sweden, Germany, and a Deceased.