Given that the beneficial effect of immediate ART on risk of severe bacterial infection seems to be partly mediated by induced rises in CD4 cell count, we considered whether the effect would be lower in people with baseline CD4 cell counts above the median of 651 cells per μL than people with baseline CD4 cell counts below the median, but the univariable effect of immediate ART was similar to the overall effect (HR 0·43; 95% CI 0·24–0·80, p=0·007). The gene discussed is CD4; the disease is bacterial infectious disease.