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Yellow fever outbreak mission

Epidemiologist Veerle Vanlerberghe travelled to Angola in May on a mission to investigate a yellow fever outbreak

In late April B-fast contacted ITM to identify outbreak/arbovirosis experts for a potential mission to investigate the yellow fever (YF) outbreak in Angola within the framework of the European Medical Corpse Public Health team.

Once the Minister of Health of Angola accepted the mission, team members were told to obtain their visas as soon as possible to be able to leave a few days later. Veerle Vanlerberghe joined a team of eight people: two epidemiologists/outbreak experts from ECDC (European Centre for Disease Control), an epidemiologist from Germany, a clinician from Portugal, a local ECHO expert and two EC staff for administrative, organizational and logistical support.

The mission aimed at reviewing the Angolan epidemiological situation and the control measures implemented, in order to advise the Angolan health authorities, to assess the risk of YF importation in the EU and the risk for EU residents, and to provide advice to the EC. The mission has been organised in agreement with the Government of Angola and in close coordination with World Health Organization (WHO). It was prepared and deployed in the framework of the European Union Civil Protection Mechanism (EUCPM), making first time use of the recently launched European Medical Corps (EMC).

The full technical report will be available soon, but in the meantime ECDC updated their risk assessment report based on het missions’ findings.

The epidemic, which started on December 5th, 2015 is declining, but not yet under control and is still expanding over the country. Up till the end of May, out of 2420 suspect YF cases 736 were laboratory confirmed, of which 88 were fatal (Case Fatality Rate: 12%). The lack of control on the outbreak is partly due to the control measures (vaccination and vector control) being only implemented after case detection and confirmation of local transmission (rule of ICG in view of the scarcity of vaccines available worldwide). Halting expansion can only be reached by preventive vaccination in urban areas with high population density, intensive human movement and in areas where the vector is present. The lack of background information on the Aedes mosquito infestation levels and on the most productive breeding sites in Angola is hampering the planning for such vaccination campaigns and for efficient pro-active vector control. The restricted availability of YF vaccines makes it impossible to expand vaccination coverage (for instance to have a buffer-belt around transmission spots) in order to prevent the spreading of the disease.

The proportion of the Angolan population vaccinated is rapidly increasing. The current mass vaccination campaign is supposed to be finalised by the end of May. When that will be accomplished, about 11.2 million individuals will have been vaccinated in approximately four months. However, there are some challenges: vaccination coverage is not consistently high in areas where vaccination campaigns took place, adult males (i.e. the main YF affected population group) are difficult to reach during vaccination campaigns, and census data, on which the calculation of vaccination coverages is based, may suffer a degree of imprecision in rapidly growing urban areas of Luanda and other large towns. Geographical pockets (where transmission is still happening) exist despite acceptable overall coverage rates.

"Being on such a short mission with the EMC was a nice personal experience, I particularly enjoyed the field trip to Huila province. I could see the huge changes between my previous stay in Angola (1996-1997) and now, especially on the availability and quality of health infrastructures. I also met an ITM alumnus, former CIPS student Dr. Filomeno Fortes who is now the Head of the National Public Health Department (DNSP/MINSA)," reports Veerle.

For the latest update on the yellow fever outbreak, see WHO/AFRO page.

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