The University of Melbourne and Murdoch Children's Research Institute are studying a vaccine that works against tuberculosis, the Bacillus Calmette-Guerin vaccine. It is a live-bacterium vaccine. That means weak but not dead "Mycobacterium tuberculosis" bacteria are injected into the patient. Then their immune system learns to fight it. Over the years, scientists saw that the Bacillus Calmette-Guerin vaccine did not only protect people from tuberculosis. It protected them from other diseases too. The scientists at the Murdoch Children's Research Institute and University of Melbourne are studying the Bacillus Calmette-Guerin vaccine to see if it will protect people from COVID-19. Because this vaccine has already been used for other diseases for more than one hundred years, doctors already knew it was safe to use. As of July 2020, this vaccine is in phase III trials to see if it works on COVID-19.