| international reference preparations of typhoid vaccine. potency assay by the active mouse protection test with three different routes of immunization. | international collaborative laboratory studies on the international reference preparations of typhoid vaccine have so far failed to provide data on which international units for these vaccines can be based. further assays carried out using the active mouse protection test, with immunization by the subcutaneous, intraperitoneal or intravenous route, confirmed the findings by some workers that the international reference preparation of typhoid vaccine (acetone-inactivated) (vaccine k) was more eff ... | 1967 | 5301738 |