Rapid risk assessment: Outbreaks of yellow fever in Angola, Democratic Republic of Congo and Uganda

Risk assessment
Cite:

European Centre for Disease Prevention and Control. Rapid Risk Assessment. Outbreak of yellow fever in Angola, Democratic Republic of Congo and Uganda: Second update, 13 July 2016. Stockholm: ECDC; 2016.

​The current epidemic of yellow fever, an acute viral haemorrhagic vector-borne disease, which has seen outbreaks in Angola, Democratic Republic of Congo and Uganda, highlights the risk of infection for unvaccinated travellers. There is also a risk of further international spread through introduction of the virus into areas with a competent vector and susceptible populations. Given that outbreaks of yellow fever in urban settings have the potential for rapid spread and that significant yellow fever epidemics are ongoing in Angola, DRC and Uganda, this risk assessment evaluates the risk of yellow fever infection being introduced into Europe and sets out a range of options for response. 

Executive Summary

The risk to the EU/EEA is limited and depends on whether the virus is introduced by unvaccinated infected travellers to an area with mosquito-vectors which could transmit the virus, states the risk assessment.

Yellow fever outbreak in Angola and DRC

A total of 3 552 yellow fever cases, 355 of which fatal, were notified from 21 January to 1 July 2016. The outbreak affects all provinces in Angola. In total 1 016 yellow fever cases were noted since the last ECDC risk assessment, on 27 May, but since April, the number of new cases reported each week has declined. Imported cases from Angola have been reported in other countries: DRC, Kenya and China.

Between 1 January and 1 July 2016, the Democratic Republic of Congo (DRC) reported 1 582 suspected cases of yellow fever. Vaccination campaigns are ongoing in both countries.

Yellow fever occurring in other parts of Africa

The risk assessment provides the latest epidemiological data on current yellow fever transmission in other countries in Africa, such as Republic of Congo, Chad, Cameron, Ghana, Guinea. There is an ongoing outbreak of yellow fever in Uganda that is not linked to the outbreaks in Angola and the DRC.

Risk for travellers and residents

Unvaccinated travellers or residents in an areas with yellow fever epidemic are at risk of becoming infected.

EU citizens who travel to, or live in, countries with yellow fever transmission, should check their vaccination status and get vaccinated if needed, as well as take measures to prevent mosquito bites indoors and outdoors.

The risk of international spread is high

The outbreaks in Angola, the DRC and Uganda are significant. People in the region frequently travel by road and plane to neighbouring countries. Therefore the risk of exporting the virus to other countries is high.

The risk to the EU/EEA remains limited

The risk to the EU/EEA is limited and depends on whether the virus is introduced by unvaccinated infected travellers to an area with mosquito-vectors which could transmit the virus, states the risk assessment.

  • The risk of importation to the EU exists in relation to travellers from affected countries who are not vaccinated against yellow fever. The risk posed by EU/EEA citizens returning from affected areas is limited because it is likely that they were vaccinated before travelling.
  • The risk of local transmission in Europe is mainly related to areas where the competent mosquito vector - Aedes aegypti is present. (the Overseas Countries and Territories and Outermost Regions of the EU, as well as in the Black Sea region and Madeira).
  • EU has the sufficient laboratory capacity to detect yellow fever.

Information on transmission through substances of human origin, such as blood donation, is also included in the risk assessment. Transmission of yellow fever through donated blood has not been reported but cannot be excluded, since the virus is detected in the bloodstream.

Preventing importation and transmission into the EU/EEA

The ECDC risk assessment suggests measures to the Member states to prevent importation and transmission into the EU/EEA– considering the significant yellow fever epidemics ongoing in Angola and the Democratic Republic of Congo.