Existing studies conducted in the USA (5, 19), Brazil (20), India (21), Nigeria (22), Uganda (23), South Africa (24), Tanzania (25), and Ethiopia (8, 12, 26–29) have identified baseline cluster of differentiation 4 (CD4) cell counts, poor and fair ART adherence, not taking cotrimoxazole preventive therapy (CPT), TB preventive therapy (TPT), and co-morbidity of malnutrition as contributing factors for the occurrence of OIs, even in the ART era. This evidence concerns the gene CD4 and tuberculosis.