Although we've seen some signs suggesting Zika outbreaks may be less severe in communities without a prior history of Dengue transmission (see Nature Immunology: Previous Dengue Infection May Make Zika Infection Worse), we really don't know what impact this Asian Zika strain will have on an immunologically naive population - or for that matter - the number of people in Europe with previous Dengue exposure.
It's a big unknown, and while North America and Europe seem highly unlikely to see widespread outbreaks, there are too many ways this could go badly to ignore the threat.
So for the past 6 months the ECDC has been rolling out a series of guidance documents, Rapid Risk Assessments, and (today) a policy briefing on Zika's threat to the EU.
Preparing for Zika in the EU – Policy briefing
27 Jun 2016
To assist policymakers in preparing for possible local transmission of Zika in the EU, ECDC has produced a policy briefing which highlights preparedness measures to minimise the risk of Zika virus spreading in continental Europe. This is primarily to protect pregnant women and women who wish to become pregnant, considering the evidence of the association between Zika virus and congenital malformations of the brain of the developing foetus.
Locally acquired cases of Zika virus infection are possible in the EU this summer in countries which have a large Aedes albopictus mosquito population (a mosquito capable of transmitting Zika), and where the ecological and climatic factors favour transmission. In the Autonomous Region of Madeira (Portugal), there is a higher probability of locally acquired cases of Zika than in continental Europe as the main mosquito capable of transmitting Zika, Aedes aegypti, is present there.
Imported cases of Zika virus are already being seen in Europe as well as sexual transmission of Zika through travellers returning from affected areas, and this can be expected to continue given the high number of people travelling between the most affected regions and Europe.
Failure to adequately prepare for Zika in the EU could lead to the disease spreading more widely, resulting in greater costs for mosquito control and care for affected people, and greater concern among the general public. The briefing suggests policymakers focus on operational plans for response measures, including the capability to detect and diagnose cases early and perform surveillance, and the provision of adequate resources to sustain enhanced mosquito control.