Novel tuberculosis vaccines on the horizon.

Eleven new tuberculosis (TB) vaccines are in various phases of clinical trials. These include subunit vaccines to improve the current vaccine BCG, and recombinant BCG to substitute for BCG, both given pre-exposure to prevent active disease. A plethora of potential candidates have reached various stages of the pre-clinical development pipeline, some ready to enter Phase I clinical trial soon. A boost vaccine to top up the immunity of existing BCG is on the horizon and will have to suffice until a better candidate to replace BCG is ready. The live mutants of Mycobacterium tuberculosis show great promise, but face a myriad of regulatory challenges.