Mycobacterium bovisBCG and New Vaccines against Tuberculosis

Abstract

Several tuberculosis vaccines have been shown to reduce the risk of disease and death due to tuberculosis in humans, but only one is used in global immunization programs: Mycobacterium bovis bacillus Calmette-Guerin (BCG). The development of new tuberculosis vaccines has been informed by evolving data on the natural history of tuberculosis, by new data on the immunology of infection with and immunization against Mycobacterium tuberculosis, by reanalysis of the role of nontuberculous mycobacteria (NTM) in protection against tuberculosis, by a clearer understanding of the benefits and risks of BCG, and by molecular techniques that have permitted identification of immunodominant antigens of M. tuberculosis and new methods of antigen delivery. This chapter talks about tuberculosis in children, older children, adults, elderly, and immunocompromised hosts, health care providers and other International travelers. At least partial immune protection from tuberculosis disease results from prior mycobacterial infection, whether naturally acquired or vaccine induced. The chapter discusses mechanisms of immune control of tuberculosis, and talks about BCG vaccine. Immunization with BCG induces a mild systemic infection in healthy hosts. It has been shown that immune responses to BCG are impaired in infants with human immunodeficiency virus (HIV) infection. The efficacy of BCG against tuberculosis is described. The favorable and unfavorable characteristics of BCG are summarized. There is wide consensus that additional tuberculosis vaccine development should focus on identifying a booster vaccine to follow BCG immunization, or on developing a completely novel two-vaccine booster regimen.