However, a recent Phase II trial aimed at preventing M. tuberculosis infection in South African adolescents revealed that while BCG re-vaccination did not show efficacy in preventing initial infection (defined by a Quantiferon QFT conversion with an IFN-γ level of ≥0.35 IU per ml after day 84), it did lead to significantly lower rates of sustained QFT conversion (defined as three consecutive positive QFT results after day 84) (Tanner et al., 2019). The gene discussed is IFNG; the disease is infection.