Deferral of blood donors with risk factors for HIV infection saves lives and money in Zimbabwe.

We compared the cost-effectiveness of three strategies to avert transfusion-associated HIV infection in Zimbabwe: HIV antibody testing, deferral of donors with HIV risk factors, and deferral of donors with risk factors followed by antibody testing ("Defer/Test"). The Defer/Test strategy averted the most HIV infections. Compared with antibody testing alone, the Defer/Test strategy, using history of genital ulcer or any sexually transmitted disease as a criterion for deferral, resulted in net savings. The cost per HIV-infected unit averted using history of paying for sex or having had multiple sex partners was $ 127 and $ 773, respectively. We discern four benefits of risk factor-based deferral before antibody testing. First, deferring donors at risk lessens collection of blood in the window period. Second, deferring donors likely to be HIV positive minimizes the number of units discarded. Third, ascertainment of donor risk provides an opportunity for AIDS education and prevention. Fourth, the number of false negatives is lower with a lower HIV prevalence among accepted donors. The Defer/Test strategy is cost-effective in Zimbabwe because additional recruitment costs are offset by discarding fewer HIV-positive units. We predict the Defer/Test strategy will be cost-effective in other sub-Saharan African donor populations.