Beyond BCG: the potential for a more effective TB vaccine

The 'Bacille Calmette-Guerin' (BCG) vaccine has been used throughout most p arts of the world for the majority of the century. It is safe to use and ch eap to produce, but there have been increasing doubts about its effectivene ss. These doubts could not come at a worse time, as tuberculosis (TB) rates continue to rise, compounded by the AIDS epidemic, and outbreaks of tuberc ulosis caused by multidrug-resistant strains are more common even in advanc ed countries. As a result, there is now a concerted research effort to prod uce new TB vaccine candidates. These include DNA vaccines, recombinant and auxotrophic vaccines and subunit vaccines, all of which hold promise, The r eal difficulty will probably arise at the clinical trial level, when a deci sion must be made either to replace BCG or to boost existing BCG-induced im munity using these new-generation vaccines.