[Prevalence of hyperimmunization against tetanus and systematic adverse reactions to tetanus toxoid in children].

Background And Aims: during the last 30 years we have observed only two children (aged 6 and 3 years) with systemic reactions after tetanus vaccine, given unnecessarily 5 and 10 months after appropriate primary immunization. The adverse reactions after tetanic toxoid appear to be directly related to excessive titre of protecting antibodies. The aim of this paper is to investigate the concentration of tetanus antibodies, which may help to define the risk of adverse reactions.

Methods: tests were carried out in 190 children (86 male, 104 female) aged 7 (n=95) and 14 (n=95) years. Antibodies to tetanus toxoid were determined using a commercial EIA.

Results: all examined children had protective concentration of tetanus antibodies (above 0.01 IU/ml; range from 0.1 to 6.0 IU/mL). There were significant differences between antibodies concentrations (GMC) in children aged 7 and 14 years (0.93 vs. 1,76 IU/ml; p=0.048). The antibodies concentrations above 1 IU/ml which indicate long term protection were more frequently observed in children aged 14 than those aged 7 years (73 vs. 59%; not statistically significant). Only 6.84% of all examined children (n=190) had high antibodies concentration above 5 IU/ml, which could increase the risk of side effects if the next booster would be given during the next 5 years.

Conclusions: children in Poland are only slightly exposed to risk of severe side effects after vaccination against tetanus. The tetanus immunity in examined children can be assessed as very good.