Xenotransplantation and the harm principle : Factoring out foreseen risk

Xenotransplantation – the transplantation, implantation, or infusion of live cells, tissues or organs from a nonhuman animal source into humans – has been suggested as the most imminent strategy to alleviate the shortage of human grafts. The pursuit of this technology is nonetheless restricted by an unquantifiable risk that the use of animal grafts will unleash new zoonoses that may affect the public at large. This paper is concerned with what the proper response to this public health threat should be. We will demonstrate that the regulatory measures taken to prevent secondary infections currently do not warrant full-blown protection of public health. That reality forces us to reconsider the extent to which the public should be guaranteed protection from a xenotransplant-related health hazard. In pondering that question, we will suggest that the permissibility of health hazards posed by emerging (bio)technologies is dependent on the perception that the benefits are both substantive and attainable and on the duty to account for foreseeable risks. In that sense, there is both good and bad news for the acceptability of xenotransplantation. An increased understanding of the infectious agents that are known to pose a health risk, relates the man-made health threat to risks that have a natural origin. 1 The risk of a xenogeneic pandemic On 18 January 2006, 90,628 patients were enlisted on waiting lists for an organ transplant across the US (OPTN 2006). Between January and October 2005 a 'mere' total of 23,511 solid organ transplants were conducted from 12,090 (both living and cadaveric) donors nationwide (UNOS 2006). The gap between supply and demand creates a considerable annual death toll. For instance, in 2003, the US Organ Procurement and Transplantation Network reported a national total of 7,147 deaths among the 114,442 patients then on the waiting list (UNOS 2004). That amounts to an average of 19 to 20 deaths a day. Researchers are developing new technologies that yield the outlook of virtually limitless supplies of transplantable grafts. One of those possibilities is the use of organs, cells and tissues from specially bred, genetically modified pigs, a procedure named xenotransplantation. According to the proponents of this emerging biotechnology, the use of porcine grafts will alleviate the burden of organ disease sooner than alternative strategies, such as the use of artificial replacements or regenerative medicine (Cascalho and Platt, 2005). Specially engineered pigs could also provide suitable organs for infants, for whom the organ shortage …