Pertussis Antibodies in Pregnant Women. Protective, Agglutinating and Complement-Fixing Antibodies before and after Vaccination.

It was reported previously 1a, b that pertussis-protective antibodies were found in a large percentage of patients who whooped three weeks or longer, that these antibodies were seldom found earlier in the disease and that they were present in all patients who had recently recovered from pertussis. Agglutinins were found in less than one half of the patients who were tested during the infection and in only a small percentage of those tested after recovery. Complement-fixing antibodies were found in some of the patients during the infection but not after recovery. The results obtained in these studies showed that the development of protective antibodies seemed to parallel the development of immunity during convalescence or after recovery and that the presence of these antibodies may be taken as presumptive evidence of immunity to pertussis. Since agglutinins and complement-fixing antibodies were seldom found during convalescence or after recovery and when they were