Comparative studies on the significance of in vitro data of BCG vaccines

In vitro parameters of BCG vaccine, such as colony-forming units or bacterial weight, are significant with respect to efficacy and occurrence of side effects only for vaccines which are made by one manufacturer according to one method and tested in one laboratory. With respect to colony-forming units from different products, widely varying doses must be applied to gain comparable effects. Similar effects can be expected from the human dose, recommended for each particular product. These conclusions, derived from experiences in vaccination against tuberculosis can also be considered essential for comparative immunotherapy with BCG vaccines.