[Prevention of tetanus in man and animal following injury]

The effect of heterologous and homologous antitoxin is the same if an equal amount of antitoxin is present in the organism. In man there are no circulating antibodies in the blood after the first injection of the toxoid because there is no natural immunity against the tetanus antigen. After the second injection, man develops the same immunity as animals. Large antitoxin doses protect people for a longer period than small doses. Normally 3,000 I. U. of the heterologous antitoxin protects people for 2 to 3 weeks. In man and sheep 2 ml of the adsorbed vaccine produces an earlier and longer-lasting immunity than 0.5 ml. Simultaneous active and passive prophylaxis is superior to passive prophylaxis alone. To achieve a long-lasting active immunity, 2 ml of the vaccine should first be injected and a booster dose 7 to 10 days later, and again 6 to 12 weeks after the first dose. Immediate vaccination against tetanus following an injury will not protect a person who has not been vaccinated previously, as the active immunity will start too late.