Epidemiology of Diphtheria in the 1990s

Abstract

Introduction Respiratory diphtheria, a severe systemic illness caused by toxigenic strains of Corynebacterium diphtheriae, was one of the most common causes of death among children in the pre-vaccine era. Diphtheria toxoid vaccine was developed in the 1920s. Widespread immunization led to the virtual elimination of diphtheria in developed countries by the 1960s and to a marked reduction of diphtheria cases in developing countries in the 1980s. The control of diphtheria has resulted in a larger proportion of adults lacking immunity as a result of failure to vaccinate or waning immunity among the vaccinated in the absence of exposure to infection. In the early 1990s, epidemic diphtheria re-emerged in the Newly Independent States (NIS) of the former Soviet Union after 30 years of control and caused thousands of deaths, primarily among adults. This paper briefly reviews the epidemiology of diphtheria in developed and developing countries, focusing on the 1990s, and comments on recent laboratory developments.