Shortage of live intravesical BCG vaccine

The American Society of Health-System Pharmacists reports a shortage of live intravesical BCG vaccine. This vaccine contains live but weakened tuberculosis bacteria. It is injected into carcinomas of the urinary bladder, hence the name intravesical. It is also approved for early stage papillary tumors that recur after surgery. The exact mechanism of action of the vaccine is unknown, but presumably the body's immune system reacts strongly to wall off the injected bacteria into a benign lump called a granuloma and in the process develops antibodies that also kill the tumor cells.