Yellow fever – Angola
On 21 January 2016, the Ministry of Health of Angola notified WHO of an outbreak of yellow fever (YF). The first case (with onset date of 5 December 2015) was identified in Viana municipality, Luanda province.
As of 10 June, 3,137 suspected cases, including 345 deaths, had been reported from all the 18 provinces of Angola. A total of 847 cases had been laboratory-confirmed. The confirmed cases are from 78 districts of 16 provinces. Local transmission has been documented in 31 districts of 12 provinces (Benguela, Cuango Cubango, Cuanza Norte, Cuanza Sul, Cunene, Huambo, Huila, Luanda, Lunda Norte, Malanje, Uige, and Zaire).
Luanda and Huambo remain the most affected provinces with 1,778 cases (489 confirmed) and 508 cases (126 confirmed), respectively. The other most affected provinces are Benguela (291 suspected cases), Huila (135 suspected cases), Cuanza Sul (99 suspected cases) and Uige (54 suspected cases). The majority of the cases are aged 15 to 24 years.
Efforts to strengthen surveillance are ongoing, and the number of cases in the country is slowly decreasing, though new clusters of cases are being reported in new districts. The epidemiological trend and pattern show that YF virus circulation continues to extend to other provinces and the risk for exportation to other countries with close linkages to Angola still exists.
The epidemiological situation in Lunda Norte is of particular concern. This province shares borders with the Democratic Republic of the Congo (DRC) and regularly experiences a high flow of people and goods in and out of DRC. To date, three laboratory confirmed cases, imported from Lunda Norte, have been reported by DRC.
Public health response
The national task force is leading the response to the outbreak, under the National Director of Public Health (NDPH). WHO set up an Incident Management System (IMS) to coordinate international partners’ support to the NDPH. The IMS integrates and coordinates the work of several organizations, including the Institut Pasteur of Dakar, UNICEF, Centers for Disease Control and Prevention, Medicos del Mundo and Médecins Sans Frontières.
The IMS partner response to the outbreak is articulated around five pillars:
- strengthening surveillance, with a focus on case investigations and laboratory confirmation
- vector control,
- case management, and
- social mobilization.
As of June 10, almost half of the country had been vaccinated (10,641,209 people) and the country had received 11,635,800 vaccines. Mass vaccination campaigns have taken place in all the districts of Luanda, seven districts of Benguela, five districts of Cuanza Sul, five districts of Huambo, three districts of Huila, and two of Uige. Vaccination is ongoing in two districts of Lunda Norte and one in Zaire, all of which border DRC. Additional mass vaccination campaigns are being planned in these and other provinces, including Cuando Cubango, Cunene and Namibe. Reactive vaccination has taken place in Cafunfu town (Lunda Norte) and the city of Lubango (Huila), among others. Plans are under way to complete vaccination in areas with low vaccination coverage (so called ‘mop up’ campaigns) in Luanda and Benguela.
WHO and partners are providing technical and financial support to the response. The current challenges include the need to strengthen the response to the outbreak at the provincial level and address border health issues.
WHO risk assessment
The evolution of the epidemiological situation in Angola is concerning and needs to be closely monitored. Based on experiences from previous similar events, it is expected that additional cases will be reported. The reports of YF imported cases in China, DRC, and Kenya demonstrate the threat that this outbreak constitutes to the entire world. Viraemic patients travelling to areas where competent vectors and susceptible human populations are present pose a risk for the establishment of local cycles of transmission. There is an urgent need to continue strengthening the quality of the response in Angola and to enhance preparedness in neighbouring countries and in countries that have diaspora communities in Angola. WHO continues to monitor the epidemiological situation and conduct risk assessments based on the latest available information.
Yellow fever can easily be prevented through immunization provided that vaccination is administered at least 10 days before travel. WHO, therefore, urges Members States especially those where the establishment of a local cycle of transmission is possible (i.e. where the competent vector is present) to strengthen the control of immunisation status of travellers to all potentially endemic areas.
In the context of an ongoing YF outbreak in Angola, special attention should also be placed on travellers returning from Angola and other potentially endemic areas. If there are medical grounds for not getting vaccinated, this must be certified by the appropriate authorities.
WHO does not recommend any restriction of travel and trade to Angola based on the current information available.