Study of specific immune response to unadsorbed concentrated tetanus vaccine administered by intradermal route to non-immunized persons in the last ten years.

Investigations of anti-tetanus response, in 404 subjects, most of them aged 60, being non-immunized for at least 10 years, stressed out the fact that 28.7% were not protected and 6.18% presented a protecting titer of 0.01 IU/ml, evaluated by "in vivo" protection test in mice. Some subjects were immunized with unadsorbed Tetanus vaccine (10 Lf/0.1 ml/dose) by i.d. route, using Jet-injector, and the others with adsorbed Tetanus vaccine (0.5 ml/dose), by i.m. route, using the needle and syringe. The vaccines were well tolerated and adverse reactions were not recorded. After 30 days, a single vaccine dose produced a protecting effect in 97.45% of non-protected subjects, belonging to i.d. immunized group, and also in 93.33% belonging to i.m. immunized group. 30 days after the administration of a second dose, protection set up in all subjects, no matter of vaccine type and administration route used. For a continuous reduction of tetanus morbidity, the authors suggest a specific periodical immunization of non-protected persons, selected by serological screening, using unadsorbed Tetanus vaccine, administered by i.d. route by means of the Jet-injector.