Abstract
The author presents a comprehensive study of the use of alum-precipitated pertussis vaccine and of alum-precipitated combined pertussis vaccine and diphtheria toxoid for active immunization. In general, the results indicate a good degree of protection against pertussis following a dosage of 30,000,000,000 organisms distributed in 3 injns. over a period of 5 weeks. The results appear similar to those in a previous series in which 70,000,000,000 organisms were injd. over a period of 3 weeks. These observations suggest that the period over which the vaccine is administered should receive as much consideration as the total dosage. Following the use of alum-precipitated combined pertussis vaccine and diphtheria toxoid, good antigenic response to both the pertussis antigen and the diphtheria, toxoid was demonstrated by immunological tests. An interim tabulation on incidence indicates protection against pertussis following injection of the combined antigen.