Combined Immunization Against Diphtheria, Tetanus and Pertussis in Newborn Infants

This investigation was undertaken to determine the capacity of newborn infants to produce antibodies. One hundred and ninety-eight infants were inoculated against diphtheria, tetanus and pertussis. A triple combined antigen containing aluminum hyroxide-adsorbed tetanus and diphtheria toxoids and 20 billion/cc. H. pertussis organisms was used. First injection (0.5 cc.) was given at seven days, second (1.0 cc.) at five weeks and third (1.0 cc.) at nine weeks of age. A booster dose of the same triple combined antigen (0.5 cc.) was given between six and 12 months of age. Local and systemic reactions to 403 injections showed an increase in the number and severity of systemic reactions with subsequent injections; no such difference was observed in local reactions. Five sterile abscesses were noted in more than 500 injections, an incidence of about 1%. No neurologic complications were observed. More than half the newborn infants tested showed diphtheria antitoxin levels of 0.03 units/cc. or more before inoculation. In 98% of those tested at one week of age, agglutinins against H. pertussis could not be demonstrated. Fifteen percent of newborns studied had detectable levels of tetanus antitoxin before prophylactic inoculation. One month after a third injection all infants tested had tetanus antitoxin levels of 0.1 unit/cc. or more ("protective level"), 92% reaching "high" antitoxin levels of more than 1.0 unit/cc. At this same age, 13 weeks, 84% had diphtheria antitoxin levels of 0.03 units/cc. or more ("protective level"). After booster dose this percentage increases from 84% to 99%. One month after completion of inoculations about 60% of the children had pertussis agglutinin levels considered "protective" (1:400). A booster dose failed to elicit any change in the number of patients with these high agglutinin titers. However, the booster caused a decrease in the percentage of infants showing an absence of pertussis agglutinins in the serum after the three initial injections. It is concluded that newborn infants do produce antibodies in response to antigenic stimuli. Response to booster dose was further evidence of the immune status of most of these patients. Further evaluation of the data and a comparison of antibody production in newborn infants with that of older children will be undertaken in a subsequent paper.