BCG, a vaccine also known as Bacillus Calmette-Geurin, has been around for over 100 years. It was developed from a strain of bovine tuberculosis that was cultured repeatedly for over 100 generations until it was unable to cause disease but was still able to confer immunity. It is used widely and safely almost everywhere else in the world to vaccinate newborns against tuberculosis. In the United States, we have a smaller incidence of tuberculosis. Rather than vaccinate all, we test all infants for tuberculosis exposure and treat only those who test positive. In spite of its lack of publicity, BCG is showing great promise in the treatment of many different types of disease.
While it was developed over time between WWI and WWII, BCG did not come into widespread use until after WWII, when it was credited with avoiding the outbreak of tuberculosis which typically follows major conflicts. As of 2004, the vaccine was being administered to over 100 million children per year around the world. It is generally effective in preventing tuberculosis and, when it does not prevent it, keeps it from becoming active tuberculosis in most cases.
Exactly how BCG affects the immune system is unclear but it clearly does more than simply protect against the onset of tuberculosis.
Cancer Treatment: Since 1977, BCG has been the accepted standard of care in the treatment of bladder cancer, where it is used as a form of immunotherapy. Immunotherapies stimulate the body’s immune system to respond to a disease. When BCG is injected into the bladder of a bladder cancer patient, it stimulates the patient’s body to attack the cancer cells. Immunotherapy with BCG prevents recurrence in up to 67% of superficial bladder cancer cases.
BCG is also used as an additive to other cancer vaccines to make them more effective. Studies are underway to evaluate its effectiveness as an immunotherapy in the treatment of colorectal cancer.
Mycobacteria: BCG provides some protective effect against the development of leprosy and buruli ulcer, a debilitating condition causing painless, open sores on the arms and legs. Both of these diseases are caused by mycobacteria. Tuberculosis is also caused by a mycobacterium.
Autoimmune Diseases: Autoimmune diseases are diseases in which the body’s immune system attacks its own cells. There are many of them and they are increasing in frequency, especially in the industrialized western countries. Among the autoimmune diseases are multiple sclerosis (MS), lupus erythematosus, rheumatoid arthritis, celiac disease, myasthenia gravis, psoriasis, vasculitis, inflammatory bowel disease, Guillain-Barre syndrome, and Type 1 Diabetes. BCG has shown promise in treating autoimmune diseases. In ways that are not understood BCG appears to dampen the body’s immune response and lessen or perhaps even reverse some of the damage caused by the immune system attacks. Human studies have shown BCG can reduce and prevent muscle damage in MS patients. Animal studies have shown great promise and human studies are underway in other autoimmune diseases with some exciting results so far.
In Type 1 Diabetes the immune system attacks and destroys the beta cells in the pancreas which produce insulin. Insulin is necessary for the body to convert glucose in the bloodstream to energy for the cells. Patients with Type 1 Diabetes will die unless they receive daily doses of insulin. Dr. Denise Faustman at Massachusetts General Hospital has reported using BCG therapy to restore a small number of Type 1 adult patients to very near normal blood glucose levels. As a result they need little or no insulin. Other studies have yielded mixed results. Dr. Faustman is now conducting much larger tests and including pediatric patients to determine the efficacy of BCG as a treatment for Type 1 Diabetes.
Persons with Type 1 Diabetes do not respond well to vaccines for Covid-19. However, BCG has been found to increase the resistance of these patients to Covid infections and to reduce their severity, should the patient become infected.
Allergies: Vaccinations of infants with BCG has shown a significant reduction in allergies among these children as they grew.
Infant Mortality: In addition to the specific applications described above, BCG has been shown to have a general and positive effect on infant mortality in developing countries. As with its effect on autoimmune diseases, the exact cause of this beneficial effect is not clear.
As a recent medical journal article on BCG stated, “[M]uch remains to be learned about its clinical effects and its mechanisms of action. During its 100-year history, the BCG vaccine has taught us that we cannot use conventional wisdom to understand an unconventional vaccine. Its durability, safety, cost-effectiveness, and ability to modify immunity warrant continued investigation.”
