Emerging infectious disease agents and blood safety in Australia: spotlight on Zika virus

In reply:

We thank Wiwanitkit for the comments on our review.1 We agree that the absence of reported transfusion-transmission of Zika virus (ZIKV) in Australia is not definitive evidence that this type of ZIKV transmission has not occurred or will not occur in the future. However, we believe that our statement indicating that ZIKV currently represents a low risk to blood safety in Australia is appropriate. Risk mitigation in the context of blood safety requires multiple strategies. In particular, we note that all countries that are endemic for ZIKV or have experienced outbreaks are subject to donor travel deferrals — either 120 days if the country is endemic for malaria or 4 weeks if endemic for dengue or chikungunya viruses but not malaria. These travel-related deferrals substantially reduce the risk of a returned donor, who may have been infected while travelling, presenting to donate while asymptomatic and viraemic. Moreover, no autochthonous cases of ZIKV have been reported to date in Australia.

Wiwanitkit’s comments do highlight the need for ongoing surveillance and appropriate responses to new information. This surveillance is possible in Australia as ZIKV is a publicly reported notifiable infection and reference laboratories have well developed protocols to perform diagnostic tests for ZIKV. Current surveillance indicates that the ZIKV-associated risk to blood safety in Australia has substantially decreased in 2017 to date compared with 2016. After a record number of reported ZIKV infections in 2016 (102 imported cases), only five cases have been reported in 2017 to 4 November.2