[Status of tetanus immunity at the age of 10 years as a function of the introduction of compulsory vaccination: study of a sample of schoolchildren in Genoa].

Immunity to tetanus of 231 girls from Genoa, attending the last class of elementary school (average age 10) have been studied. According to the vaccination tables of the Public Health Service, these girls received a minimum of 4 to a maximum of 9 inoculations of vaccine (Diphtheria-Tetanus toxoid). The antitoxic antibodies have been titrated by passive-haemoagglutination method using antigen-coated lyophilized avian red cells. All subjects observed had high titer antitoxic antibodies. Comparing the antibodies titer with the time elapsed after the last vaccination, the result was that the average titer lowers progressively; the reduction becomes statistically significant after three years. All the 145 girls, who had 4 or 5 doses according to a regular calendar, had an antibody titer equal or major than 0.4 I.U./ml, after 5 years from the last dose.