The routine injection of diphtheria toxoid during the latter part of the first year of life has almost completely eliminated diphtheria in most localities; and, during the time that infants after the age of 7 months have been injected with potent pertussis vaccine, whooping cough morbidity and mortality have decreased at an encouraging rate.
Because diphtheria and whooping cough are most prevalent and serious in the first years of life, it seemed logical that immunization against the two diseases should be attempted at the same time by the injection of mixtures of diphtheria toxoid and potent pertussis vaccine. When this investigation was begun in 1938 only Bordet1 had published a brief report on the use of a mixture; but he gave no data on immunity tests for either disease nor did he report clinical evidence of protection.
A satisfactory mixture of these antigens when injected subcutaneously should not be
SAUER LW, TUCKER WH, MARKLEY E. IMMUNITY RESPONSES TO MIXTURES OF DIPHTHERIA TOXOID AND PERTUSSIS VACCINE. JAMA. 1944;125(14):949-952. doi:10.1001/jama.1944.02850320007003