CD4 and COVID-19: In the first published cohort study analyzing co-infection of TB and COVID-19 across 8 countries, 49 cases of co-infection were explored and it was found that a diagnosis of COVID-19 may occur before, simultaneously, or after a diagnosis of tuberculosis [52] A case report of a 40 year old female diagnosed with COVID-19 and TB suggested that CD4+ T-cell depletion associated with COVID-19 may be implicated in the progression of LMTBI to active TB in a similar manner to Human Immunodeficiency Virus (HIV) [53].