Due to risk of HIV transmission, the FDA recommends a ban on blood donation from men who have sex with men (MSM). Revised in 2015, the current restriction applies to men who have had sex with a man in the year before donation. Given advances in HIV testing and the option of risk-based screening, the current approach may not represent the optimal strategy for ensuring a safe blood supply.
Using a decision tree, we compared 3 strategies: 1) the current standard: a deferral for MSM followed by 4th generation HIV antibody/antigen (Ab/Ag) and viral load (VL) testing of all donated units; 2) test-only: no deferral, with Ab/Ag and VL testing; 3) risk-based: deferral for all male donors who report condomless anal intercourse in the past 6 weeks, followed by Ab/Ag and VL testing. The primary outcome was the expected number of accepted HIV+ donations per million units of donated blood. Key input parameters include MSM prevalence (3.6%), HIV testing sensitivity for chronic (99.96%) and acute (75%) infection, and false negative rate of the current MSM deferral question and the risk-based screening question (2.6% for each). In sensitivity analyses, we assessed the impact of variation in these parameters.
In the base case, the current strategy resulted in 5.39 HIV+ accepted blood donations per million; the testing only strategy resulted in 7.10 HIV+ accepted blood donations per million; and the risk-based strategy resulted in 2.54 HIV+ accepted blood donations per million. In sensitivity analyses, the risk-based strategy was superior across plausible ranges of HIV test sensitivity and MSM prevalence. The risk-based strategy was superior when the false negative rate generated by the risk-based screening question was <10.4%; at higher rates, the current strategy was superior. The current strategy was superior when the MSM deferral question yielded <0.8% false negative rate; at higher rates, the risk-based strategy is superior. Compared with the current standard, a risk-based strategy could add 5 million low-risk MSM to the potential donor supply.
A risk-based screening question, combined with Ab/Ag and VL testing, may be more effective than the current strategy. The quality and ability of screening questions to accurately assess risk is key to any pre-donation screening strategy.
R. Walensky, None