[Investigation of the immunity status towards tetanus of a population of mechanics at the car-factory "Renault" (author's transl)].

Tetanus immunity has been studied in a population of mechanics working at the car-factory "Renault". For the study, 283 individuals were divided into 3 groups. The first group consisted of non-vaccined individuals, the second of vaccinated individuals and the third of individuals who had been boostered. The influence of different parameters on tetanus immunity status was considered, i. e. the age of the subjects, the time at which boostering was given, the serotherapy (when it was administered) and the contact with machine lubricating and cooling fluids. Clostridium tetani bacilli and spores were frequently found in aqueous machine fluids. Their presence is a potential hazard for non-vaccinated mechanics coming to contact with the fluids. Tetanus antibody levels in the sera of the tested population were determined in vivo by the toxin neutralization test. The influence on tetanus immunity of the different parameters considered in this paper was subjected to statistical analysis. From the whole population, 27% of the individuals were found to have no protection against tetanus. When age was taken into account, 53% of the individuals over 45 years old and 10% of those under 45 years old were shown to be devoid of tetanus immunity. It could be shown that younger individuals were better protected than older ones, because the formers had been immunized with adsorbed tetanus toxoid and most of the latters with fluid toxoid. Of the individuals in the third group who had received a booster injection within 15 years after primo-vaccination, 98% showed protective tetanus antibody levels in their sera in contrast to 25% when boostering had occurred more than 15 years after primo-vaccination. Contact with machine fluids was found to influence the degree of immunity of only those individuals whose boostering dated back to more than 25 years. Unexpectedly, 3 mechanics seemed to develop immunity after coming into contact with machine fluids. From the results reported here, it is concluded that tetanus immunity in vaccinated individuals should be renewed by a compulsory booster injection given every 5, 10 or, at the minimum, 15 years. Moreover, high-risk populations such as that represented by the mechanics should be immunized or boostered on commencing employment.