Tuberculosis vaccines

Abstract

Preventing transmission of the Mycobacterium tuberculosis (Mtb) is the best strategy to interrupt the global tuberculosis epidemic. Vaccination should therefore aim at preventing lung disease in adults, and at preventing Mtb infection. The current vaccine, Bacillus Calmette Guerin (BCG), is about 80% effective at preventing disseminated tuberculosis in young children, but protection against adult lung disease is generally poor. Uncontrolled data suggests that BCG could prevent Mycobacterium tuberculosis (Mtb) infection in certain settings: these results and proposed next steps will be discussed. New prime vaccines aim to replace BCG, while other candidates aim to boost T cell immunity primed by BCG, by environmental mycobacteria or by Mtb infection. Novel approaches that induce non-natural immunity for prevention of infection will be discussed. In the setting of a primed host response, vaccine-induced “modulation” of host response may be a more appropriate description of the vaccination goal, compared with “boost”. New results of protective host responses against disease will be discussed. New approaches to tuberculosis vaccine clinical trials aim at efficiency and at early up selection of candidates. Examples of how these trials could be used to learn about protective host responses, which, in turn, would further inform vaccine development, will be provided.