Importantly, in a mouse model of TB, when using 24 vaccine regimens consisting of three BCG strains (BCG, BCG::ESX1Mtb, and a derivative of BCG::ESX1Mtb) and eight combinations of vaccine delivery, we recently demonstrated that the inclusion of ESX1-exported effector molecules was the overall most efficient way to improve BCG performance [27]. This evidence concerns the gene ESX1 and tuberculosis.