CD4 and tuberculosis: Compared to CD4 counts of <350 cells/μl, a high CD4 count was associated with lower TB incidence, 81% lower for a CD4 count of 350–500 cells/μl (IRR 0.19, 95% CI 0.04–0.08) and 85% lower for those with a CD4 count above 500 cells/μl (IRR 0.15, 95% CI 0.04–0.64).