ECDC Zika epidemic rapid risk assessment includes updated risk classification approach

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​The Zika epidemic remains a significant concern for public health. The latest update of ECDC’s rapid risk assessment on the Zika epidemic includes an assessment of the level of risk for travellers based on an adaptation of the WHO interim guidance on the Zika virus country classification scheme and the recent epidemiological and scientific information.

The Zika epidemic remains a significant concern for public health. The latest update of ECDC’s rapid risk assessment on the Zika epidemic includes an assessment of the level of risk for travellers based on an adaptation of the WHO interim guidance on the Zika virus country classification scheme and the recent epidemiological and scientific information.

ECDC adapted WHO revised country classification

The ECDC adapted WHO classification replaces the previous ECDC classification of Zika virus infection. It has been developed to categorise the epidemiological profile of vector-borne Zika virus transmission in countries and territories and to provide a more accurate reflection of the level of risk to travellers.

The categories are:

  • Areas with virus transmission following virus new/re introduction (WHO Cat. 1)
  • Areas with virus transmission following previous virus circulation (WHO Cat. 2)
  • WHO category 2 areas with new documented intense transmission
  • Areas with interrupted transmission (WHO Cat.3)
  • Areas bordering a WHO category 2 area (sub-category of WHO Cat. 4)
  • Areas with potential for transmission (sub-category of WHO Cat. 4). 

Risk to Europe

Pregnant women are still considered the most important risk group and the primary target for preventive measures because Zika virus infection during pregnancy is associated with intrauterine central nervous system infection, congenital malformations and foetal death.

It is expected that Zika-viraemic travellers will continue to return to the EU. However, the risk of onward transmission is extremely low due to the present low activity of Aedes albopictus. During the summer, autochthonous transmission in the EU following the introduction of the virus is possible in areas where Aedes albopictus is established. However, there is no clear evidence of this mosquito species being able to sustain a Zika virus outbreak on their own.