Studies of the age incidence of the communicable diseases have served to point out the high resistance of the new-born infant to certain diseases and a lack of resistance at this age to other diseases. Measles, scarlet fever, diphtheria and poliomyelitis occur infrequently in infants, and to these the new-born infant appears to be immune. No immunity is observed to smallpox, chickenpox, whooping cough or pyogenic infections. This selective immunity of the new-born infant to communicable diseases is of the passive type and presumably is derived from the mother by means of the placental or mammary transmission of antibodies.
The presence in blood obtained from the umbilical cord of antibodies to diphtheria,1 scarlet fever2 and poliomyelitis3 has been demonstrated. The immunity of the new-born infant to measles, if the mother has experienced the disease, has been pointed out by Herrmann,4 and by Debré and Joannon.5