CD4 and infection: The CD4 + count (estimated within the six months of subjects’ enrolment) was used for immunological staging of infection severity: Stage 1 representing CD4 + count of > 500 cells/mm3, Stage 2, CD4 + count of 350–499 cells/mm3, Stage 3, CD4 + count of 200–349 cells/mm3 and Stage 4, CD4 + count of < 200 cells/mm3.