[Table of Contents]

Volume: 27S1 • July 2001

Report of the Xenotransplantation Surveillance Workshop
Infection Control Database and Sample Archiving

OVERVIEW

Why an Enhanced Surveillance System for Xenotransplantation in Canada?

The potential for a novel, zoonotic agent to gain hold in the human population through xenotransplantation protocols is internationally recognized as a grave concern for public health. Although not all zoonotic agents can or will lead to pandemics or epidemics, the examples of HIV and "mad cow disease" (new variant Creutzfeldt-Jakob Disease [vCJD]) are recent prototypes of serious, latent infections that humans have probably acquired from animals. HIV has widely decimated lives and has threatened blood safety around the world, requiring testing for the agent to reduce risk. As yet, the transmission of prion mediated disease or vCJD has not been demonstrated to occur through the use of blood or blood products. Nevertheless, precautions have been undertaken on the basis of a theoretical risk. For example, the United Kingdom (U.K.), the country most affected by vCJD, now imports plasma from countries that have not reported cases of vCJD to make pooled blood products. Canada does not accept blood donors who have lived for more than 6 months (cumulative) in the U.K. and, more recently, in France. Unlike the case with HIV, there is no effective screening tool to reduce the risk of transmission of vCJD. The containment and control of zoonotic agents and the negative impact on blood availability or safety are problematic and costly for public health. Prevention of new epidemics, if possible, would be the preferred option.

The infectious agents of most concern to xenotransplantation and blood safety are those producing silent infections that are latent for many years and that result in incurable and devastating disease. In Canada, no clinical trial applications involving xenografts have been received or authorized to date. Thus, in accordance with the recommendations of the National Forum on Xenotransplantation, held in November 1997⁽¹⁾, Canada has a unique opportunity to put into place precautionary measures that will allow us to more carefully assess and at the same time minimize the infectious disease risks associated with xenotransplantation clinical trials. An enhanced surveillance system for infectious agents associated with xenotransplantation is essential for this purpose.

On March 31, 2000, the Xenotransplantation Surveillance Workshop was hosted in Ottawa by the Bloodborne Pathogens Division of the Bureau of Infectious Diseases,* Laboratory Centre for Disease Control, Health Canada, to obtain comments from experts on an enhanced xenotransplantation surveillance system that would best meet the needs of Canadians. The workshop was not intended to be a consensus conference but, rather, to examine the issues and to serve as a starting point for future deliberations on xenotransplantation surveillance, including public debate.

Twenty-six infectious disease and xenotransplantation experts together with two observers attended the workshop (see Appendix A). The morning plenary session covered the goals and objectives of setting up enhanced xenotransplantation surveillance and summarized the recommendations of the 1997 National Forum on Xenotransplantation. This was supplemented by a brief discussion of the draft Proposed Canadian Standard for Xenotransplantation. The international surveillance issues that were covered included a report by the U.S. Centers for Disease Control and Prevention. The morning session concluded with an overview of the U.S. pilot xenotransplantation database. During the afternoon session, a discussion on databases and sample archiving was conducted, guided by specific survey questions (see Appendix B).

This report provides a background to the current framework for xenotransplantation regulation in Canada and and addresses the main xenotransplantation surveillance concerns. The survey results are compiled, reviewed and interpreted in the context of this background, which includes a discussion of the Proposed Canadian Standard for Xenotransplantation.

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