Blood donor selection remains the first level of defense against TTIs; the deferral of high-risk prospective donors is a primary strategy to reduce risk. The favored source of blood collection in the developed world is VNRBD because such donors have been found to have lower risk for TTIs, at least in developed countries. For this reason, VNRBD is exclusively advocated by the WHO and is component of the 2012 objectives, that is, at least 80% VNRBD.
Voluntary donors are typically recruited through centralized systems, for example, blood centers that remain independent of the hospital. Voluntary and nonremunerated blood donation is logistically complex, requiring strategized recruitment, marketing, and collection to secure and, consequently, retain sufficient numbers of donors to approximate demand. This is reflected in the cost: a unit of blood collected through a centralized system is 2 to 3 times more expensive than that collected through replacement donation (RD; defined as donation from family members or friends of the patient), the major alternative to VNRBD in Africa [3
In addition to financial support, VNRBD via centralized blood centers requires a developed infrastructure to be sustainable, for example, storage and refrigeration, transportation, communication, and QA, all of which are often ill developed in a resource-poor setting. Deficiencies in transport and storage have particular adverse effect in Africa where blood is prescribed for medical emergencies; the ability to tolerate delays, incumbent to procuring blood from outside the hospital, is poor.
Replacement donation is the major alternative to VNRBD and the primary source of blood collection in much of Africa. Estimated to contribute 75% to 80% of transfusable blood in the region [4
], replacement donors comprise friends or relatives of the intended transfusion recipient. Although similar in concept, the term directed donor
is used in developed countries when blood is donated and reserved for a specific recipient. This category of donor has long been regarded as higher risk based upon the assumption that friends or relatives are more likely to deny or ignore risk factors that invite further inquiry, removing the protection afforded by risk-screening questionnaires in favor of a perceived coercion to donate. Family members may also be at higher risk than VNRBD for some TTIs because of ethnicity, for example, hepatitis B virus (HBV). Furthermore, where burdened with the responsibility to procure donors urgently, family members may surreptitiously pay donors for their services, thereby compounding transfusion risk. Frequent shortcomings of RD include inadequate testing of units, lack of QA, and poor record keeping because of collection in the hospital setting where transfusion oversight is often poor. The latter may partly account for the enormous variability in data pertaining to RD [5
Replacement donation is, however, significantly cheaper than VNRBD; in 1 study in Malawi, the cost of a unit collected through RD was shown to be $16 vs $56 for a unit collected from a centralized system [6
]. This cannot be ignored in a financially constrained environment. Replacement donation is logistically easier than volunteer donation as it does not require the infrastructure or recruitment mechanisms associated with VNRBD; rather, collection takes place at the hospital [5
], and the burden or responsibility for recruiting donors shifts to the patient’s family and friends. This proves successful owing to the strong cultural bonds and extended family support evident in much of Africa.
There is a delicate balance between the need for the lower risk VNRBD, an ideal, albeit expensive and resource intensive strategy, vs RD, a less-demanding mechanism that may both inadvertently promote collection from high-risk donors as well as burden families and friends with the responsibility of procuring donors. This has prompted many to rethink the validity of exclusive or aggressive VNRBD and to closely reexamine the risk attached to any given subset of donor. In fact, some studies have shown that the assumption of higher TTI prevalence among RD compared with VNRBD may not always be true in Africa. A recent study from Ghana examined transfusion risk for HIV and HBV; the prevalence of anti-HIV and hepatitis B surface antigen in first-time volunteer vs replacement was 1.03% and 13.8% vs 1.1% and 14.9%, respectively [7
]. The lack of difference between VNRBD and RD has also been shown in Latin America: HIV prevalence was indeed found to be higher among Brazilian VNRBD than RD donors after controlling for first-time vs repeat donor status [8
], and no statistical difference was noted in TTI prevalence between VNRBD and RD in blood donors in a border population in Mexico [9
These studies point out the importance of obtaining country-specific TTI prevalence data and of controlling for first-time vs repeat donor status when making comparisons between VNRBD and RD. The first-time donor is considered high risk for HIV and other TTIs [10
]; these donors are usually young with concomitant higher prevalence of sexually transmitted TTIs, have uncertain or untested motive to donate, and, by definition, have had no prior transfusion screening. Indeed, many first-time donors use donation as a means to access HIV testing, itself an unavoidable donation incentive [11
There have been novel strategies adopted to facilitate VNRBD and to convert first-time donors to regular donors, some of which have been very successful. One example pioneered in Zimbabwe is Club 25, through which secondary school donors pledge to donate 25 U during their lifetime [12
]. Another approach in Ghana witnessed partnership between a teaching hospital and a local FM radio station; continual appeal for blood donors resulted in 63.6% repeat donation over a 3-year period, a feat achieved at low cost [12
]. There have also been proposed strategies that build on the availability of RD while retaining safety.
Shortfall in provision of blood remains a multifaceted problem in Africa with direct adverse effect on clinical care. The impact on maternal mortality is one such poignant example where 26% (16%–72%) of maternal hemorrhage deaths are presently ascribed to lack of blood [13
]. Strengthening the existing replacement-based model through on-site recruitment of voluntary donors, investment in hospital transfusion services with testing, QA, and data collection may be preferable and improve the transfusion shortfall. Further consideration of RD vs VNRBD ought to be driven by data on TTI prevalence and/or incidence in the 2 types of donors in the local setting. Many replacement donors share a similar altruism to VNRBD and can be used effectively while still maintaining transfusion safety. The component triage policy used by the South African National Blood Service (SANBS) may be a viable approach for the future. In recognition of the high risk attached to first-time donors, SANBS preferentially uses blood products from repeat VNRBD except in time of shortage.
Beyond debate of VNRBD and RD, deficient recruitment of blood donors remains an enduring problem in much of Africa. Shortfall in recruitment is a complex problem rooted in culture, education, and marketing. Successful donor recruitment relies on knowledge of the epidemiology of blood donation in the region; this information is often deficient or lacking in Africa. Available data indicate that the African donor pool is skewed toward young donors, likely reflecting recruitment in secondary schools and universities, and is disproportionately male. The latter may, in part, be cultural where men in Africa are perceived as being healthier than women [14
], as well as physiological where iron deficiency anemia, pregnancy, and breastfeeding preclude women from joining the donor pool [15
]. Broadening donor demographics represents a mechanism to bolster numbers; this should, however, be tempered by prevalence data on TTIs.
Education and literacy are also notable obstacles to recruitment; in a study in Burkina Faso, 30.8% of blood donors were illiterate or of primary school level. More poignantly, 14.4% donated to access HIV testing [11
], highlighting a need to communicate both the utility as well as the risks of blood transfusion.
Donor profiling and risk assessment is contingent on availability of robust epidemiological data, revisiting the fundamental need for situational analysis. This includes demographic and behavioral risk factors for sexually and parenterally acquired infections, for example, HIV, HCV, and syphilis as well as knowledge of geographic risks for infections, for example, malaria and arboviruses. To some extent, collection practice and donor deferral can be adapted accordingly, particularly if a risk is localized, for example, chikungunya (CHIKV). It becomes more difficult to absorb the impact on the donor pool if the infectious agent is hyperendemic to the area, for example, malaria.
Finally, the donor pool in Africa is affected by anemia, malnutrition, and infectious disease, all of which directly or indirectly affect donor eligibility. In a Malawi-based study, 35.6% of prospective donors were deferred for hemoglobin level less than 12 g/dL or a positive infectious disease marker, 10% of which was for HIV, 2% venereal disease research laboratory test positivity, 1% HBV, and 5.8% for positive malaria slides [6