[Persistence of antibody levels for 5, 10 or more years after tetanus vaccination and immunological response to a "booster" immunization].

By means of the indirect haemagglutination test the rate of antitetanic antibodies in male individuals (532 subjects), vaccinated from 5 or more years has been estimated. According to the time elapsed from the last administration of the vaccine three groups have been formed: vaccinated from 5 to 10 years (353 subjects), from 11 to 15 years (133 subjects), from over 15 years (46 subjects). According to the previous vaccine history, the group, being considered, resulted as being composed of: 86% vaccinated with 3 doses, 13% vaccinated with 2 doses, while the vaccinated rate with 1 dose (8 men) appeared practically negligible. 79.0% of this population resulted as being completely protected (limit 0.1 I.U./ml) and 94.2% resulted as being protected at the minimum limit (0.01 I.U./ml) The number of those protected diminished as the time elapsed from the vaccination increased. Considering the limit 0.1 I.U./ml, there are values of 87.9% for the group 5-10 years, 80.1% for the group 11-15 years and 76.0% for the one of those over 15 years. Considering the limit 0.01 I.U./ml the above-mentioned values result respectively equivalent to 95.3%; 94.1%; 87.0%. The administration of the booster has determined effective increases of the antibody rates; after one month from the inoculation the number of the non protected (less than 0.01 I.U./ml) appears completely nonexistent and the number of those protected at the minimum limit results contained in 1.2%. In conclusion we suggest the extension of the interval for the booster from 4 to 8-10 years as well as we suggest a review of the legislation which provides complete vaccination for all those who undertake a wide range of agricultural or industrial works prescinding completely, at the time of their engagement, from the state of immunity of the subjects to be treated.