Strong, multifunctional CD4+ T cells specific to BCG were produced by BCG revaccination in healthy individuals.BCG revaccination was immunogenic and decreased the rate of sustained QFT conversion in adolescents.The BCG-Denmark immunization in Brazilian healthcare professionals did not decrease the risk of QFT Plus conversion.BCG revaccination in HIV-negative adolescents without QFT tests did not offer protection against sustained Mtb infection.A Malawi study conducted on repeat BCG immunization without a placebo showed no significant protection against TB. This evidence concerns the gene CD4 and tuberculosis.