An aspiration to radically shorten phase 3 TB vaccine trials.

A new tuberculosis (TB) vaccine is a high priority. However, the classical development pathway is a major deterrent. Most TB cases arise within two years after M. tuberculosis exposure, suggesting a three-year trial period should be possible if sample size is large to maximise the number of early exposures. Increased sample size could be facilitated by working alongside optimised routine services for case ascertainment, with strategies for enhanced case detection and safety monitoring. Shortening enrolment could be achieved by simplifying screening criteria and procedures and strengthening site capacity. Together, these measures could enable radically shortened phase 3 TB vaccine trials.