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

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.

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).

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.

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.