IN cash-starved regions of the world, deciding who should get anti-retroviral drugs for HIV is a tough call. Now it seems that one of the main tools for making that decision may be less reliable than it appeared.
World Health Organization guidelines recommend starting anti-retroviral drugs when someone’s CD4 cell count has fallen below 350 cells per microlitre, an indicator of HIV infection, or for people with symptoms of AIDS whose CD4 count has dropped to below 200.
Brian Williams of the WHO and his colleagues studied HIV-positive and HIV-negative populations in eight African countries including Ethiopia, South Africa, Uganda…
