Rapid risk assessment: Zika virus disease epidemic - 7th update, 12 July 2016
This seventh update assesses the risks associated with the Zika virus epidemic currently affecting countries in the Americas, taking account the latest information available. It provides updated information for those travelling to and returning from affected countries and for EU citizens residing in areas with active transmission. It reviews available information on the association between Zika virus infection and congenital central nervous system malformations, including microcephaly, as well as the association between Zika virus infection and Guillain–Barré syndrome. It also assesses the risk of local vector-borne transmission in Europe during the 2016 summer season and proposes a range of mitigation measures for EU/EEA Member States to consider.
Imported cases are expected to be reported continuously during the summer in EU, while the risk of local transmission is considered to be low to moderate, states the latest update of ECDC risk assessment on the Zika epidemic in the Americas and the Pacific.
As of 1 July 2016, local cases have been reported from 49 countries or territories worldwide - over the past three months. In the EU (continental Europe): no local transmission has been reported; 977 imported cases were recorded in 20 EU/EEA countries.
ECDC closely monitors the evolution of the Zika epidemic and regularly updates its risk assessment. The outbreak has a direct impact on the risk of importation and possible local transmission of Zika to the EU, in areas where the competent mosquito vectors of Zika are present - especially now in the summer season, when the mosquitoes are active.
Although Zika is generally considered a mild mosquito-borne disease, evidence exists of an association between the Zika virus infection during pregnancy and congenital malformations in new borns; an infection can cause an autoimmune neurological disease in adults, Guillain–Barré syndrome.
Important to note in this update of the risk assessment:
- Although there is an association between Zika virus infection and complications during pregnancy, it is not known yet at what stage of the pregnancy the foetus can be affected. The latest research shows growing evidence that Zika virus infection during the first and second trimester is associated with increased risk for microcephaly. The risk for central nervous system malformation of the foetus associated with infection during the third trimester is unknown - hence, Zika virus infection should be considered as a risk throughout the entire duration of pregnancy.
- Following WHO updating its guidance on prevention of sexual transmission of Zika, ECDC has aligned the suggested mitigation options for travellers returning from Zika-affected areas:
- Travellers returning from areas with ongoing Zika virus transmission should be advised to use a condom for at least 8 weeks after returning, in order to reduce the potential risk of onward sexual transmission. If before or during that period Zika virus symptoms occur, men should use condoms or consider abstinence for at least six months.
ECDC Risk assessment
- Travel-related risk for EU citizens: Travellers to Zika-affected countries are at risk of becoming infected through mosquito bites. Pregnant women and women who are trying to become pregnant are a high-risk group, due to the serious adverse outcomes of Zika virus infection.
- Risk of importation and transmission in continental EU: Cases of Zika virus infection arriving from countries with local transmission continue to be reported in the EU and it is expected that this will continue during the summer in Europe. The risk of local transmission through mosquitoes is considered to be low to moderate.
- Risk of Zika virus transmission via substances of human origin: The limited data indicate that there is a potential risk of Zika virus transmission through substances of human origin such as blood that may cause serious consequences to the health of recipients. The primary measure to prevent Zika virus transmission in non-affected areas and areas with sporadic transmission is the temporary deferral of donations from blood donors.