CD4 and COVID-19: Since CD4 T cells are crucial key players in the immune defense against TB, the exhaustion of T cells in COVID-19 patients can not only contribute to the reactivation of latent TB but also the aggravation of an existing active TB infection during TB-COVID-19 co-morbidity (163–165) Besides, anti-inflammatory drugs such as corticosteroids administered to treat COVID-19 patients have the potential to create an immunosuppressive state which creates opportunities for different infections including reactivation of latent TB to occur (166).