In addition, another modelling study showed close impacts of the treat-all strategy and an extension of the eligibility for ART (from <350 to <500 CD4 cells/mm3): using several mathematical models, it has been shown that, in South Africa, this extension would prevent 5 to 12 % new infections whereas an extension to all HIV-positive individuals would prevent 9 to 32 % new infections over 20 years depending on the mathematical model and assuming no additional testing and linkage to care [35]. This evidence concerns the gene CD4 and infection.