Sepsivac Injection is used both as a vaccine and as a treatment for certain bacterial infections. This medicine contains Mycobacterium W cells which have been killed by heat. It is used in the treatment of infections like leprosy or to treat or prevent infections in people undergoing treatment for lung cancer. Leprosy is a chronic condition affecting the skin and the nerves, caused by Mycobacterium leprae. Nausea, vomiting, diarrhea, weight loss are some of the common side effects associated with this injection.