[Level of immunity against diphtheria among the personnel of a Hamburg hospital and in the normal population (author's transl)].

Diphtheria antitoxin titres were measured by passive haemagglutination in a total of 4542 blood samples obtained between the end of 1980 and beginning of 1981 from staff at Hamburg hospitals and from randomly selected age-matched persons (1219). Among the hospital personnel 67.5% had no protective diphtheria antitoxin (less than or equal to 0.11 IU/ml), compared with 52% among the control group. Among those aged 15-24 years, 60.2% of staff were unprotected, compared with 46.6% of the control population. The geometric mean value of the diphtheria antitoxins also gave a worse immunity level for hospital personnel (0.08 IU/ml) than the control population (0.14 IU/ml). While geometric mean titre values of hospital staff beyond the age of 45 fell nearly continuously, those in the control population rose with increasing age.