Emerging Pathogen Threats in Transfusion Medicine: Improving Safety and Confidence with Pathogen Reduction Technologies

The increasing frequency of emerging infectious diseases is driven by globalization, increased human-animal interaction, and climate change. These changes increase human exposure to novel pathogens, including those transmissible through blood products. Blood transfusions are crucial for various medical conditions but carry the risk of transmitting infectious diseases, particularly to vulnerable populations. Historically, blood safety measures have been reactive, responding to identified threats. However, the unpredictable nature of emerging pathogens necessitates proactive strategies. Pathogen reduction (PR) technologies offer a proactive approach by inactivating or removing pathogens from blood components before transfusion. This review focuses on the Mirasol PRT system, which uses riboflavin and UV light, and assesses its effectiveness against several recently emerged viruses.

The review extensively cites existing literature on emerging infectious diseases and their impact on transfusion medicine. It covers the history of bloodborne pathogen transmission, the evolution of blood safety measures (from immunological assays to nucleic acid-based tests), and the development and implementation of pathogen reduction technologies. The literature reviewed includes studies on various PR systems (Theraflex MB, Intercept, Mirasol, Theraflex UV Platelet), their mechanisms of action, and their effectiveness against different pathogens. A significant portion of the literature review focuses on the transmission dynamics and risks associated with specific emerging viruses like HIV, HBV, HCV, arboviruses (West Nile, Dengue, Zika), and the recently emerged SARS-CoV-2, mpox, Ebola, and Hepatitis E viruses. The use of convalescent plasma as a therapeutic tool and the associated risks are also reviewed.

This is a review article, not an experimental study. The methodology involves a comprehensive literature review focusing on emerging viral pathogens (mpox, SARS-CoV-2, Ebola virus, and hepatitis E virus) and their potential impact on transfusion safety. The authors critically examine existing literature to assess the risks associated with these viruses and evaluate the efficacy of pathogen reduction technologies in mitigating these risks. The primary focus is on the Mirasol PRT system, which uses riboflavin and UV light to inactivate pathogens in blood products. The authors analyze published data on the effectiveness of the Mirasol system against these specific viruses, including in vitro studies evaluating viral inactivation rates and the preservation of therapeutic components (e.g., neutralizing antibodies in convalescent plasma). The findings from these studies are then synthesized to assess the role of Mirasol PRT in improving blood safety and pandemic preparedness.

The review highlights the significant threat posed by emerging viruses to blood transfusion safety. The authors demonstrate that the Mirasol PRT system, based on riboflavin and UV light, effectively inactivates several emerging viruses in various blood components. Specifically, studies showed that Mirasol reduced mpox virus titers to below detectable levels in plasma and whole blood; inactivated SARS-CoV-2 in plasma and whole blood, reaching the limit of detection at 60% of the target energy dose for plasma and achieving a 3.30 log10 average viral reduction in whole blood; inactivated Ebola virus in nonhuman primate serum and human whole blood to non-detectable levels without impacting protective antibody titers; and reduced Hepatitis E virus titers by >2-3 logs. The review also notes that the Mirasol system preserved neutralizing antibodies in SARS-CoV-2 convalescent plasma, maintaining its therapeutic potential. The COVID-19 pandemic is cited as an example of how emerging viral threats can severely impact blood supply, emphasizing the need for proactive pathogen reduction strategies. While reactive measures like donor screening are effective, they are inadequate to address unpredictable emerging threats. The authors emphasize that the Mirasol PRT system offers a pathogen-agnostic approach, providing an additional layer of safety even against newly emerging pathogens for which testing may lag.

The findings of this review strongly support the use of proactive pathogen reduction technologies, such as the Mirasol PRT system, to enhance blood transfusion safety. The system's effectiveness against a range of emerging viruses, including those with unknown or uncertain transmission risks, makes it a valuable tool for pandemic preparedness. The review emphasizes that while current testing methods and donor screening are essential, they are not sufficient for mitigating the risks associated with unpredictable emerging pathogens. The use of PRT complements these strategies and reduces the risk of transfusion-transmitted infections, particularly during outbreaks when rapid responses are needed. The limitations of existing PR technologies, such as variable effectiveness against different pathogens, are acknowledged. However, the Mirasol PRT system's broad-spectrum efficacy and the preservation of therapeutic components in treated blood products make it a significant advancement in improving blood safety. The successful implementation of universal component pathogen reduction, as seen in a pilot study, further supports the potential of this technology.

This review highlights the critical need for proactive pathogen reduction technologies in transfusion medicine to address the ever-evolving threat of emerging infectious diseases. The Mirasol PRT system demonstrates effectiveness against multiple emerging viruses while preserving therapeutic benefits, significantly improving blood safety. Future research should focus on optimizing PRT technologies for all blood components, ensuring cost-effectiveness and broad accessibility, furthering efforts to maintain a safe and reliable blood supply.

As a review article, this study is limited by the scope of the available literature. The effectiveness of the Mirasol PRT system may vary depending on specific viral strains and blood product types. The review primarily focuses on the Mirasol system and does not provide a comprehensive comparison of all available pathogen reduction technologies. Cost-effectiveness analyses may vary depending on regional epidemiological contexts.