An effort to lower the communicability rate of infants immunized with H. pertussis in the usual fashion has led to a critical evaluation of certain factors in this routine immunization. First, the optimum age at which to start immunization for pertussis remains 6 to 9 months. Theoretical analogy with other immunizations and Sauer's discouraging results under 6 months, more than counterbalance the recent report of Sako and associates. In a small group, (20) infants from 3 to 6 months of age, this paper shows a failure of protection as judged by agglutination tests. Until clinical evidences of immunity are forthcoming, as judged by actual protection to exposure, infants should not be inoculated before 6 months of age. Second, the type of vaccine to be used is reviewed. The use of alum-precipitated vaccines of H. pertussis is condemned on the ground of frequent severe reactions, and occasional abscess formation. Sako and associates, using a total dose of only 40 billion, found abscess formation in 0.6 per cent. If the dosage of 80 to 120 billion commonly accepted as necessary for clinical protection were employed, the abscess formation might reach as high as 10 per cent, in the author's experience. The use of combined vaccines, H. pertussis with diphtheria toxoid, or with diphtheria toxoid and tetanus toxoid is also condemned on the same ground if the vaccine is alum-precipitated. Third, the total dosage to be given, originally set at 80 billion, is now recommended to be 120 billion, both on serologic and clinical results cited. Two hundred infants from 6 to 9 months of age, given 120 billion, showed a communicability rate of only 9.6 per cent as compared with an average of 33.9 per cent for those given 80 billion. Fourth, the time interval between inoculations, originally set at one week apart, is now recommended to be four weeks apart, both on serologic and clinical experience cited from the literature. Fifth, the concentration of the vaccine to be employed, originally set at 10 billion to the cubic centimeter, is now recommended to be 20 or 40 billion to the cubic centimeter. A study of three groups of children inoculated with 15, 20, and 40 billion concentrations, with a total dosage of 120 billion, showed statistically insignificant variations in reactions, as judged by pain, local swelling, and fever. © 1946 The C. V. Mosby Company.
Lapin, J. H. (1946). Immunization against whooping cough. The Journal of Pediatrics, 29(1), 90–94. https://doi.org/10.1016/S0022-3476(46)80243-9