Infectious risks of transfusion: a 10-year look back and perspectives.

Almost 50 years following the advent -and ensuing tragedy- of transfusion-transmitted HIV, infectious diseases continue to shape blood transfusion practice and policy. Over the past decade alone, a myriad of changes span innovation in donor selection, testing and pathogen reduction, to emergence and re-emergence pathogens that have required evaluation and, in some cases, active intervention. Major developments include refined bacterial testing, novel findings on cold storage of platelets along with the expanded use of pathogen reduction to address the risk of bacterial contamination. Notable pathogens include Zika virus, Plasmodium (malaria), Babesia (babesiosis) and SARS-CoV-2 (COVID-19), the latter spurring a historic pandemic. SARS-CoV-2 highlighted the potential for emerging infectious diseases to impact the blood supply, independent of whether transfusion transmissible. The pandemic afforded new insight into convalescent plasma and how passive immunotherapy can be used to treat infectious diseases. Other favorable developments include a transition to individualized risk assessment and the relaxation of longstanding donor deferral policies (e.g. variant Creutzfeldt-Jacob disease), which have helped to alleviate the transfusion deficit. Progress in artificial intelligence and machine learning has yielded novel tools for surveillance and horizon scanning that enable early recognition of threats and opportunities for transfusion services to contend with infectious diseases. Nonetheless, many of the favorable developments do not extend to low and low-middle income countries, where replacement donation, suboptimal laboratory-based screening with limited molecular testing, and near-absent post-transfusion surveillance, continue to contribute to transfusion transmitted infection. We reflect on the impact of infectious diseases on transfusion services over the last ten years (2016-2026).