PREVALENCE OF HYPERIMMUNIZATION AGAINST TETANUS IN ITALIANS BORN AFTER THE INTRODUCTION OF MANDATORY VACCINATION OF CHILDREN WITH TETANUS TOXOID IN 1968

Systematic mandatory immunization of children against tetanus was star ted in Italy in 1968. Prevalence of tetanus hyperimmunization (> 5 IU/ ml) was assessed among 214 immune subjects born after 1968 and found t o be 17.3%. This figure is significantly higher (p < 0.01) than the 10 .8% found in a previous study of subjects born before 1968. This incre ase is statistically significant in the Center (p < 0.01) and in the S outh (p < 0.05) of Italy, but not in the North. Hyperimmunization is n ot associated with family size (odds ratio 2.16; C. I. 95% = 0.5-7.6) or the father's years of education (odds ratio 1.83; C. 1. 95% = 0.6-5 .3). No difference was found between urban and rural areas of residenc e. Indiscriminate administration of booster doses of tetanus vaccine i n hyperimmune subjects in some areas could result in unnecessary vacci nations, which can cause hypersensitivity reactions.