Prospects for a new, safer and more effective TB vaccine.

Tuberculosis in infants and young children remains an all too common cause of morbidity and mortality in high burden countries, despite the fact that the majority of these children receive vaccination with BCG in infancy. BCG confers incomplete and variable protection against pulmonary tuberculosis [PTB] and is unsafe in HIV positive persons. Newer TB vaccines, which, it is hoped, will either replace or complement BCG are being developed and a number of these have reached the stage of clinical trials, with two booster vaccines going into Phase IIB trials in 2009. Prospects for at least one new licensed TB vaccine within the next 5-10 years appear reasonable. This article explores some of the issues around the development of new vaccines against TB and details the leading candidates.