Multi-stage subunit vaccines against Mycobacterium tuberculosis: an alternative to the BCG vaccine or a BCG-prime boost?

摘要

Since 1921, the BCG vaccine, a viable attenuated strain of Mycobacterium bovis bacillus Calmette-Guerin, has been the only available vaccine against tuberculosis (TB). The vaccine shows relatively good efficacy against severe forms of the disease (i.e. tuberculous meningitis and miliary TB) in new-borns and children, and it is routinely administered to infants in most epidemic areas [1,2]. However, the BCG vaccine is unable to control and eliminate TB worldwide; its protective efficacy remains controversial. For example, its protective efficacy against pulmonary TB in adults, the most common form of the disease, is inconsistent (0-80%) [1-5]. Furthermore, it does not prevent the reactivation of dormant Mycobacterium tuberculosis {Mtb) [1-5]. Therefore, there is an urgent need for a novel, safe, and more effective TB vaccine that prevents all forms of TB, particularly latent TB infection (LTBI).