Curbing the HIV Epidemic: Universal HIV Testing and Immediate HAART Initiation

HIV threatens to kill about 3 million people each year. Southern and East Africa are particularly badly affected and one-quarter of all HIV-positive people live in southern Africa. In 2007 3 million people, 10% of those living with HIV, had been given anti-retroviral therapy (ART) but another 2.5 million became infected. While ART has greatly reduced AIDS related mortality it has had little impact on HIV transmission. HIV has also increased the incidence of tuberculosis (TB) by up to 7 times in African countries. While ART reduces the risk of TB in HIV-positive people current practice has not significantly reduced the incidence of TB. We consider the conditions under which ART could be used to reduce HIV transmission and TB incidence. Since ART reduces viral load in HIV-positive people it reduces their infectiousness but the extent to which it reduces transmission also depends on the time between sero-conversion and the start of treatment. The risk of TB increases exponentially with time since HIV-seroconversion and the extent to which ART reduces TB transmission also depends on the timing of treatment. Dynamical models are used to estimate the impact of ART on HIV and TB in 9 countries in sub-Saharan Africa for which good trend data are available for both infections. These countries, Botswana, Gabon, Ghana, Lesotho, Malawi, Tanzania, South Africa, Swaziland and Zambia, account for 31% of all HIV-positive people in the world. A policy of testing people once a year, on average, and starting them on ART as soon as they are found to be HIV-positive, test-and-treat, would reduce HIV transmission and mortality by 95% by 2015 and HIV prevalence by 95% by 2050, and would reduce TB incidence by 50% by 2015 and by 95% by 2050. A less ambitious policy in which people start ART five years after HIV-sero-conversion, when their CD4+ cell count is typically 350 cells/μL, would reduce the incidence and prevalence of HIV by between 25% and 75% in 2050 and the incidence of HIV-related TB by about 63% in 2050 but would not eliminate either infection. Between now and 2050 test-and-treat would reduce new HIV infections by 99.2% averting 59 million cases, AIDS related deaths by 74% saving 34 million lives, and new TB cases by 50% preventing 11 million cases. In South Africa, which has 17% of all people living with HIV in the world, the cost of such a programme would peak at about US$2.5 billion per year in 2015 but would decline thereafter and, given the economic cost of AIDS related diseases and mortality, it could be cost-saving within a few years. Using ART to prevent HIV as well as to treat AIDS could lead to effective control of HIV and TB in generalized HIV epidemics. This has important implications for policy and funding. Frequent HIV testing and early ART could substantially reduce TB incidence in sub-Saharan Africa but the elimination of  HIV infection and HIV-related TB would only be possible if HIV-positive individuals start ART within one year of sero-conversion.