Blood-Borne Pathogens: A Canadian Blood Services Centre for Innovation Symposium

Abstract

Testing donations for pathogens and deferring selected blood donors have reduced the risk of transmission of known pathogens by transfusion to extremely low levels in most developed countries. Protecting the blood supply from emerging infectious threats remains a serious concern in the transfusion medicine community. Transfusion services can employ indirect measures such as surveillance, hemovigilance, and donor questioning (defense), protein-, or nucleic acid based direct testing (detection), or pathogen inactivation of blood products (destruction) as strategies to mitigate the risk of transmission-transmitted infection. In the North American context, emerging threats currently include dengue, chikungunya, and hepatitis E viruses, and Babesia protozoan parasites. The 2003 SARS and 2014 Ebola outbreaks illustrate the potential of epidemics unlikely to be transmitted by blood transfusion but disruptive to blood systems. Donor-free blood products such as ex vivo generated red blood cells offer a theoretical way to avoid transmission-transmitted infection risk, although biological, engineering, and manufacturing challenges must be overcome before this approach becomes practical. Similarly, next generation sequencing of all nucleic acid in a blood sample is currently possible but impractical for generalized screening. Pathogen inactivation systems are in use in different jurisdictions around the world, and are starting to gain regulatory approval in North America. Cost concerns make it likely that pathogen inactivation will be contemplated by blood operators through the lens of health economics and risk-based decision making, rather than in zero-risk paradigms previously embraced for transfusable products. Defense of the blood supply from infectious disease risk will continue to require innovative combinations of surveillance, detection, and pathogen avoidance or inactivation.

Keywords: Blood-borne pathogens; Health economics; Next generation sequencing; Pathogen inactivation; Transfusion; Transfusion-transmitted infection.

Fig 1

The Risk-Based Decision-Making framework. The Risk-Based Decision-Making framework was designed by the Alliance of Blood Operator to help blood operators identify, assess, act on, and communicate risk in decisions related to blood safety. It is a flexible tool, and its objectives are to optimize the safety of the blood supply while recognizing that elimination of all risk is not possible; allocate resources in proportion to the magnitude and seriousness of the risk and the effectiveness of the interventions to reduce risk; and assess and incorporate the social, economic, and ethical factors that may affect decisions about risk , , .

Fig 2

Emerging Infectious Disease ToolKit. The Emerging Infectious Disease ToolKit is a framework developed by the AABB Transfusion-Transmitted Diseases, Emerging Infectious Diseases subgroup to guide health professionals and public health officials in triaging and managing infectious threats to the blood supply. The EID tool-kit presents: a variety of methods for EID surveillance; key questions to be asked when a threat is suspected; and potential courses of action based on the situation .