For example, a study from The Gambia [12] and Colombia [13] reported increased IFN-γ response to Rv2031 in household contacts compared to community controls whereas investigators of the VACSEL Study Group in Ethiopia and The Gambia [14] and another independent study from Ethiopia [15] reported significantly increased IFN-γ in community controls compared to both TB patients and contacts. Here, IFNG is linked to tuberculosis.