BCG vaccine is commonly administered either enterally, that is, by mouth, or parenterally, that is, subcutaneously or intradermally. The enteral or oral method has been used in New York City since the beginning of 1927. The statistics concerning its value are favorable; still we have felt the need of the parenteral method. The advantages of this procedure compared to the oral are:
It can be given to patients of any age, provided they are free from tuberculosis and give a negative tuberculin reaction.
The control of the dosage is more exact than if we depend on absorption of the bacilli from the alimentary tract, from which only a small part of the orally given vaccine is absorbed and the other part excreted.
Those who believe that hypersensitiveness to tuberculin parallels immunity are more satisfied with the parenteral method because in 87 per cent of the cases the
KERESZTURI C, PARK WH, SCHICK B. PARENTERAL BCG VACCINATION. Am J Dis Child. 1932;43(2):273-283. doi:10.1001/archpedi.1932.01950020003001