Persistence of antibodies against tetanus upon revaccination.

To assess the interval since the last revaccination against tetanus the persistence of antibodies was determined using ELISA test in 128 subject. Levels of antibodies against tetanus higher than the protective level of 0.1 IU/ml were found not only in those revaccinated less than ten years ago, but also in those revaccinated more than ten years before. With increasing length of the interval since last revaccination the antibody levels against tetanus decreased gradually although they remained above the protective level. No basic dependence of that trend on gender or age has been found. In the whole series, antibodies against tetanus exceeded the protective level for up to 20-25 years post last revaccination. This finding together with a favorable epidemiological situation as regards the occurrence of tetanus could eventually enable to prolong the interval for revaccinating adults in the Czech Republic.