Clinical studies of TB vaccines.

Tuberculosis will not be brought under control without making a more effective TB vaccine. The only currently licensed TB vaccine, BCG, was discovered nearly 100 years ago, confers only variable and incomplete protection again pulmonary TB and is contraindicated in infants infected with HIV. New priming and boosting vaccines have been developed, have shown promise in preclinical and early clinical studies and are now approaching Phase IIB proof of concept and Phase III efficacy trials. Likely target populations include infants, adolescents and HIV infected adults. Phase III trials will need to be multi centre, enrol very large cohorts of subjects and follow them up for at least two years for clinical endpoints. There are insufficient efficacy trial sites globally. Such sites require a combination of high TB rates in target populations, clinical and laboratory support and infrastructure, and surveillance systems capable of detecting all important and relevant events in trial participants. Over the last decade significant progress has been made in assessing potential sites and assisting them to develop the necessary capacity to participate in future efficacy trials of new TB vaccines.