Emerging infectious disease outbreaks: estimating disease risk in Australian blood donors travelling overseas

Abstract

Background and Objectives International travel assists spread of infectious pathogens. Australians regularly travel to South‐eastern Asia and the isles of the South Pacific, where they may become infected with infectious agents, such as dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) viruses that pose a potential risk to transfusion safety. In Australia, donors are temporarily restricted from donating for fresh component manufacture following travel to many countries, including those in this study. We aimed to estimate the unmitigated transfusion‐transmission (TT) risk from donors travelling internationally to areas affected by emerging infectious diseases. Materials and Methods We used the European Up‐Front Risk Assessment Tool, with travel and notification data, to estimate the TT risk from donors travelling to areas affected by disease outbreaks: Fiji (DENV), Bali (DENV), Phuket (DENV), Indonesia (CHIKV) and French Polynesia (ZIKV). Results We predict minimal risk from travel, with the annual unmitigated risk of an infected component being released varying from 1 in 1·43 million to <1 in one billion and the risk of severe consequences ranging from 1 in 130 million to <1 in one billion. Conclusion The predicted unmitigated likelihood of infection in blood components manufactured from donors travelling to the above‐mentioned areas was very low, with the possibility of severe consequences in a transfusion recipient even smaller. Given the increasing demand for plasma products in Australia, the current strategy of restricting donors returning from select infectious disease outbreak areas to source plasma collection provides a simple and effective risk management approach.

Estimation of mosquito-borne and sexual transmission of Zika virus in Australia: Risks to blood transfusion safety

“…The proportion of symptomatic ZIKV infections [ 66 , 77 – 80 ] ranges from 17–35% in Flamand et al . [ 79 ], to 20% in Lazear et al .…”

“…The other parameters were taken from Coghlan et al . [ 66 ]. We then estimated the risk of infected components being released by dividing the total number of products obtained from individual donations per year N with the estimated number of infected components released in year N. Given the severe clinical consequences to an infected foetus, the large proportion of asymptomatic cases, and the detection of ZIKV RNA in asymptomatic blood donors, we purposely did not adopt a numerical risk threshold as a trigger for additional risk mitigation for ZIKV, as this would have been too subjective, but rather adopted levels of risk (very low, low, medium, high) as a trigger for additional risk mitigation for ZIKV.…”

“…Finally, we utilized the European Up-Front Risk Assessment Tool (EUFRAT-version 2.2.31, http://eufrattool.ecdc.europa.eu/) with estimated cumulative infections to assess the transfusion-transmission risk from predicted potentially infected blood donors. EUFRAT has a webbased interface and was commissioned by the European Centre for Disease Prevention and Control (ECDC) to quantify the transmission risk through blood transfusion during outbreaks of emerging infectious diseases (EIDs) [63][64][65][66][67]. The conceptual basis of the EUFRAT is further described in Kiely et al (2017) [68].…”

“…The proportion of symptomatic ZIKV infections [66,[77][78][79][80] ranges from 17-35% in Flamand et al [79], to 20% in Lazear et al [78] and Coghlan et al [66], and 20-50% in Joguet et al [80]. In order to avoid underestimating the risks for blood supply safety, we opted for an estimate of 20% symptomatic ZIKV infections.…”