Serological survey of immunity to tetanus in adult population of Northern Halkidiki, Greece

BACKGROUND: Despite the implementation of the obligatory anti-tetanus vaccination, the tetanus cases in Greece are not eliminated. Because of the increased possibility of Clostridium tetani infection of the Northern Halkidiki population--like any other rural population the evaluation of the immunity to tetanus in the area is considered necessary. METHODS: The tetanus antitoxin levels were determined using the enzyme-linked immunosorbent assay (ELISA) in 405 healthy adult individuals attending the health center for routine laboratory tests. RESULTS: 64.4% of the studied population was found protected (tetanus antitoxin levels > or = 0.1 IU/ml). The percentage of protected people decreased as age increased from 83.3% in the 21-30 to 51.2% in the > 60 age group. 82.1% of the tested males and 52.6% of the tested females had tetanus antitoxin levels > or = 0.1 IU/ml (p < 0.0001). The percentages of immune men (100-66.2% in various age groups) were found higher than those of women (80.8-35.5% in the respective age groups). The geometrical mean titres (GMTs) were 0.44 in all of 261 immune people, 0.53 in 133 immune men and 0.37 in 128 immune women (p = 0.0021). CONCLUSION: The proportion of protection among men over 60 and women over 30 years old is inadequate, the levels of tetanus antitoxin decline with age and a significant difference was found between the proportion of protection of males and females.