CD4 and bacterial infectious disease: In this study of 7638 infants, the adjusted HRs for a serious bacterial infection were 1.7 (95% CI 1.2–2.6) and 1.2 (95% CI 0.8–1.9) for infants of mothers with CD4 count below 350 cells/μl and 350–500 cells/μl respectively, compared to above 500 cells/μl.