Transfusion Medicine. Jeffrey McCullough
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Potential donors who have resided in or traveled to malaria‐endemic areas are deferred for 12 months. However, most transfusion‐transmitted malaria is associated with lengthy residence in malaria‐endemic areas rather than routine or short‐term travel, especially when short‐term travel is concentrated in tourist areas that may have little or no risk [19].
Several questions related to AIDS risk behavior include whether the potential donor has had sex with anyone with AIDS risk factors, that is, given or received money or drugs for sex, had sex with another male (for males), or had sex with a male who has had sex with another male (for females). One area of inconsistency that has been eliminated involved whether males had sex with another male (MSM) at any time since 1977 (when HIV is thought to have entered humans). Previously, deferral had been indefinite, but this has been changed to 12 months to be consistent with other risk deferrals, and the reference to 1977 was eliminated. When the FDA changed this guidance regarding MSM in late 2015, it also committed to studying the effects of these changes on HIV risk in the blood supply through the Transfusion‐Transmissible Infections Monitoring System (TTIMS), a collaborative effort of the FDA, National Institutes of Health, and several major blood centers [20]. Although US data for the initial period since the changes have not yet been published, reports from Canada suggest that risk will not be greatly altered and that models used to estimate risk have been accurate [21–23]. In any case, when more data are available it may facilitate consideration of additional policy changes being tried in other countries, such as shorter (3 or 6 months) MSM deferral, or using other criteria to assess blood donor HIV risk that eliminates the MSM question.
Transfusion recipients can theoretically harbor unknown infectious agents and perpetrate the cycle of transmissible disease, and so deferral of previous transfusion recipients has been considered. In one very large study, a previous transfusion history was found in 4.2% of donors. However, transfused and nontransfused donors had a similar incidence of positive viral screening tests and other deferrable risks [24], and thus receipt of transfusions is not a deferral criterion.
The medical history is an extremely effective part of ensuring the safety of the blood supply. For instance, the implementation of questions about behavior that would put potential donors at risk for HIV infection decreased the HIV infectivity of blood in the San Francisco Bay area by 90% even before the use of the HIV screening test [25]. One concern that remains even today has been that people who have engaged in high‐risk behavior might seek to donate blood to obtain a test for HIV. In some situations, this seems to be true. Of 30 HIV‐positive blood donors in Paris, 47% had known risk behaviors and 50% admitted to having donated to obtain a test for HIV [26]. In a larger study of HIV‐seropositive blood donors, their reasons for donating in spite of having participated in