Tetanus Immunization: Effectiveness of the Stimulating Dose of Toxoid Under Conditions of Infection

Summary Two groups of 75 guinea pigs each were immunized with two doses of alum precipitated tetanus toxoid one month apart and subsequently infected with tetanue spores. An additional dose of toxoid was given to one of the groups at the time of infection and withheld from the other. In the group which received the extra toxoid there occurred 8 cases of local tetanus and no cases of generalized tetanus as against 13 cases of local tetanus and 4 cases of generalized tetanus in the group which did not receive the extra toxoid. There is also an indication that a larger number of animals with low antitoxic titers at the time of infection will escape without symptoms or slight symptoms if given a smultaneous dose of additional toxoid than if not so treated. A small number of animals were observed for changes in the titers of the circulating blood following infection. Those given additional toxoid showed increases in antitoxic titers by the 5th day after infection as compared to the 8th–10th day in those not given additional toxoid. The results confirm similar observations previously made by us on partially immunized guinea pigs.