Many people do not realize that TB (Tuberculosis) is still a relatively common illness. It is brought into the U.S. by travellers and immgrants. At present, two billion people worldwide are believed to have latent or dormant TB. Of those infected, but with no signs or symptoms of disease, eight to nine million will develop TB each year, of whom 1.6 million will die. While Isoniazid therapy is 90 percent effective for those who complete it, in reality, fewer than 50 percent do. . The high attrition rate can have serious public heath effects, not only for the patients who fail to complete therapy, but also for the individuals they may later infect. Four months of Rifampin instead of the current nine months of Isoniazid costs significantly less for the healthcare system and is more likely to be completed by the infected person.