Relative to participants without VF, those with VF had lower median CD4 counts (230 vs 406 cells/mm3, p < 0.0001), lower weight at first-line failure (49 vs 52 kg, p = 0.003), were more likely to have an opportunistic infection (17% vs 3%, p < 0.0001) and less likely to have optimal ART adherence (71% vs 87%, p = 0.005). Here, CD4 is linked to Opportunistic infection.