Although haemovigilance systems have been in place for nearly two decades with notable success in reducing risk, the most important issue that needs to be understood is the dissimilarities between blood safety systems and what might be implemented in cell and organ transplantation. The first relates to the volume of activity – blood donations are in the millions in many countries while organ donations are in the thousands in only a very few countries and haematopoetic stem cell donations are even fewer. The second deals with the scarcity of donors – blood donors can be replaced while organ donors are very scarce and haematopoetic stem cell donors are usually unique for each recipient.
Moreover, mortality rates on organ transplant waiting lists are substantial as are unavoidable mortality rates from transplantation. Risks from the transmission of disease are very small under standard procedures but there is the need for a critical understanding of the risk of causing more deaths than one might save through implementing specific safety strategies. It is also important to realise that the frequencies of transplants, even in the most active countries (such as the USA), are such that the data from across the world will need to be put together to be able to detect even the reasonably frequent events (1:1,000 or 1:100,000). The clinician plays an important role in this context by deciding whether or not organs are suitable for transplantation.
Ultimately, the public must be engaged in understanding the risks and benefits of transplantation as they have been in blood donation. Transparency is key in gaining public trust and involvement in the entire cycle of transplantation from donation to patient outcome. In order to better understand relative risks both numerator and denominator data are necessary to calculate the various occurrences that can occur with MPHO. Adequate data collection systems have not been universally implemented and are needed for such calculations.