Immunity against diphtheria and tetanus in German blood donors

After the recent diphtheria epidemics in Eastern Europe in the early 1990s, we re-evaluated the diphtheria and tetanus immunity of 321 German blood donors (192 men and 129 women). The mean antitoxin levels of all blood donors in this study, measured by commercial ELISA, revealed a questionable protection (0.1–1.0 IU/ml) against diphtheria. In 1994, 66.4% were without immunity against diphtheria (55.0% in 1997/98), 32.1% (41.5% in 1997/98) showed questionable protection and only 1.5% (3.5% in 1997/98) had protective antitoxin levels. The evaluation of tetanus immunity revealed only 0.5% (1.1% in 1997/98) of the subjects with no protection and 9.1% (8.5% in 1997/98) with questionable protection. For this reason, we conclude that the diphtheria epidemics only lead to an insufficient improvement of the immunization status in a healthy German population.