Design and implementation of blood donor sample bioarchives to enhance preparedness for emerging and pandemic pathogens in England.

New and emerging infections with blood-borne pathogens pose an ongoing threat to the safety of blood transfusions and transplants. Bioarchives of stored blood donor samples represent a valuable pathogen screening resource for both ensuring safety of blood transfusions and for wider public health infectious disease surveillance. Large scale testing of donors enables early detection of pathogen spread and extent of population exposure. We have implemented two complementary systems for the bioarchiving of blood donor samples in England for these purposes. The CODONET bioarchive collects samples from geographically targeted regions of potential pathogen emergence. Consenting donors provide detailed information to allow for risk assessment and, importantly, to distinguish imported from autochthonously acquired infection. Separately, the blood donor surveillance archive (BDSA) stores 100 or 200 pools of 24 randomly selected, fully anonymised donation samples from donors in England every 2 weeks, allowing large-scale continuous sampling. This enables rapid evaluation of the presence of blood-borne pathogens in donor populations and a large-scale epidemiological tool to detect pathogen emergence in real-time. Combined, these bioarchives allow for proactive assessment of donation transmission risk, and as targeted population-wide archives, contribute to public health surveillance of emerging pathogens and pandemic spread.