LOW-PREVALENCE OF DIPHTHERIA ANTITOXIN IN CHILDREN AND ADULTS IN NORTHERN GERMANY

Recent outbreaks of diphtheria in neighbouring eastern European countr ies and in the Russian Federation prompted us to evaluate immunity to diphtheria in a sample of 400 healthy individuals (210 male, 190 femal e) from northern Germany. An age-stratified study population was chose n, including newborns, children, adults and elderly persons over 60 ye ars divided into 8 subgroups of 50 persons each. Diphtheria antitoxin was tested by enzyme immunoassay. The median antitoxin titre was 0.39 IU/ml. There was no difference in the median antitoxin titres of men a nd women. Inadequate immunity to diphtheria was detected in more than 90 % of the 400 individuals tested, including 4 % who completely lacke d immunity (titre < 0.01 IU/ml), a further 20 % with minimal protectio n (titre 0.01-0.1 IU/ml) and the majority of 69 % who showed relative protection for less than one year (titre 0.1-1.0 IU/ml). Only 7 % exhi bited lasting protection for more than five years (titre > 1.1). Newbo rns and persons over 50 years of age constituted the least protected g roups, with significantly lower median antitoxoid titres than the othe r age groups (p < 0.001). The absence of protective immunity in 7 of t he 50 newborns examined (14 %) reflects the inadequate protection of w omen of reproductive age. Children aged 1 to 10 years were the best im munized and protected group. The results suggest that routine booster immunizations of the majority of the adult population would be advisab le in view of the ongoing migration from and the visits to high-risk a reas.