Availability refers to sufficient, sustainable and timely supply of new TB vaccines for adults and adolescents. This includes having demand assessed for different population groups, defining policy and evidence needs, and having procurement plans in plans. This follows from the WHO global framework for country introduction of new adolescent and adult TB vaccines (https://www.who.int/publications/m/item/who-global-framework-to-prepare-for-country-introduction-of-new-tb-vaccines-for-adults-and-adolescents)
Measuring indirect transmission-reducing effects in tuberculosis vaccine efficacy trials: why and how?
Tuberculosis is the leading bacterial cause of death globally. In 2021, 10·6 million people developed symptomatic tuberculosis and 1·6 million died. Seven promising vaccine candidates that aim to prevent tuberculosis disease in adolescents and adults are currently in late-stage clinical trials. Conventional phase 3 trials provide information on the direct protection conferred against infection or disease in vaccinated individuals, but they tell us little about possible indirect (ie, transmission-reducing) effects that afford protection to unvaccinated individuals. As a result, proposed phase 3 trial designs will not provide key information about the overall effect of introducing a vaccine programme. Information on the potential for indirect effects can be crucial for policy makers deciding whether and how to introduce tuberculosis vaccines into immunisation programmes. We describe the rationale for measuring indirect effects, in addition to direct effects, of tuberculosis vaccine candidates in pivotal trials and lay out several options for incorporating their measurement into phase 3 trial designs