Research Paper (postgraduate) from the year 2017 in the subject Medicine - Epidemiology, grade: 1.8, Egerton University, language: English, abstract: Immunotherapy approach seems to have gained a widespread application in the treatment of diseases, unlike in the past two decades when it was not considered as a significant treatment option. However, this treatment option dates back to the nineteenth century in which surgeons discovered the correlation between surgery and microbial infections, especially in post-surgery patients. For instance, William Coley, a renowned New York surgeon applied immunotherapy technique on cancer patients. This was after his realization that, some bacterial infections to post-surgery cancer patients helped to manage the disease. Coley received posthumous fame after researchers identified the beneficial bacteria as Coley toxins. Despite the success realized in the treatment of the disease, it was abandoned after new treatment techniques were discovered. Since then, immunotherapy received little attention from healthcare professionals and researchers until recently when it was found to be significant in treating most of the challenging diseases such as cancer, autoimmune diseases as well as infectious diseases.