There has been a LOT of information in the Forum over the last year about the current BCG shortage. Use the "search" function at the top of this page and you will find it all.
Briefly, BCG is as biological substance and is manufactured by only one company. It is distributed by Merck. For several years there have been manufacturing problems, according to Merck. This requires that the entire facility shut down and start over. BCG has been in short supply now for several years, and last year several months went by without it. This is a world-wide shortage.
Since it is not a patentable substance with a huge profit margin no one else is interested in producing it.
The American Bladder Cancer Society, as well as many other entities, have been monitoring this and addressing the importance of this substance with the FDA,
Merck, and other interested parties for some time.
Sara Anne