The introduction of universal childhood immunisation programmes with diphtheria toxoid in the 1950s has led to virtual elimination of diphtheria from most developed countries. In the past, the highly contagious acute infectious disease caused by toxigenic strains ofCorynebacterium diphtheriae had endangered in particular children of preschool age. Given a case fatality rate of 5% to 10%, diphtheria had been considered one of the most serious communicable diseases of childhood. The practice of routine mass immunisation of children resulted in a dramatic decline of incidence and mortality from diphtheria in many European countries, including the former Soviet Union where, by 1976, the incidence rate had fallen to 0.08 per 100 000 population.1 In 1989, a World Health Organisation (WHO) meeting endorsed a recommendation that envisaged full …