Another disadvantage is that natural infection occurs, so the absence of previous exposure to mycobacterial antigens should be confirmed by screening using an IFN-γ release assay or other method of screening and baseline lung imaging to rule out ongoing infection as recent work has confirmed that current infection with Mtb significantly protects CMs from a secondary Mtb infection (Cadena et al., 2018). The gene discussed is IFNG; the disease is infection.