[Obligatory anti-tetanus vaccination and the public health service].

Tetanus antitoxin levels were measured in a non-random group of 281 subjects of pediatric age, using a passive haemagglutination technique. 94.7% of sera had protective antitoxin levels (titer greater than or equal to 1: 1024), while the other ones had levels usually considered as partly protective (titer of 1:256 or 1:512). Subjects who completed vaccination schedule had protective levels also 6 or more years after last dose. Subjects with partly protective antitoxin levels can be identified reviewing vaccination registers and recalling people who did not complete vaccination schedule. This procedure, if used as screening test, has sensitivity of 20%, specificity of 98% and a predictive value of positive tests of 37.5%. The quality of vaccination service of the study area, assessed using three indicators, resulted fairly good.