Emergencies

Yellow fever situation report

16 June 2016

A yellow fever outbreak was detected in Luanda, Angola late in December 2015. The first cases were confirmed by the National Institute for Communicable Diseases (NICD) in South Africa on 19 January 2016 and by the Institut Pasteur Dakar (IP-D) on 20 January. Subsequently, a rapid increase in the number of cases has been observed.


Figure 1. Geographical distribution and confirmed, probable and suspected yellow fever cases and deaths in Angola and Democratic Republic of the Congo


Emergency Committee regarding yellow fever

Following the advice of the Emergency Committee (EC) convened on 19 May 2016, WHO Director-General decided that urban yellow fever outbreaks in Angola and DRC are serious public health events which warrant intensified national action and enhanced international support. The events do not at this time constitute a Public Health Emergency of International Concern (PHEIC).


Summary:

Angola: 3137 suspected cases

In Angola the total number of notified cases has increased since early 2016. As of 15 June a total of 3137 cases have been reported, of which 847 are confirmed. The total number of reported deaths is 345, of which 112 deaths reported among confirmed cases. Suspected cases have been reported in all provinces, and confirmed cases have been reported in 16 of 18 provinces and 78 of 121 reporting districts

Mass vaccination campaigns first began in Luanda and have now expanded to cover most of the other affected parts of the country, recently the campaigns have focused on border areas. Despite extensive vaccination efforts circulation of the virus persists.

Democratic Republic of the Congo: 1044 suspected cases

As of 15 June 2016, 1044 suspected (71 deaths) and 61 laboratory confirmed cases have been reported in 22 health zones in the Democratic Republic of the Congo (DRC). Of these 61 confirmed cases: 53 were imported from Angola, two are sylvatic and six are autochthonous cases.

Surveillance efforts have increased and vaccination campaigns in DRC have centred on affected zones in Kinshasa and Kongo Central.

The risk of spread

Three countries already have reported confirmed yellow fever cases imported from Angola: DRC (53 cases), Kenya (two cases) and People’s Republic of China (11 cases). This highlights the risk of international spread through non-immunised travellers.

Seven countries (Brazil, Chad, Colombia, Ethiopia, Ghana, Peru and Uganda) are currently reporting yellow fever outbreaks or sporadic cases not linked to the Angolan outbreak.

Risk assessment

The outbreak in Angola remains of high concern due to:

  • Persistent local transmission in Luanda despite the fact that approximately 8 million people have been vaccinated.
  • Local transmission has been reported in 12 highly populated provinces including Luanda. Zaire and Huambo are the provinces that most recently reported local yellow fever transmission
  • The continued extension of the outbreak to new provinces and new districts.
  • High risk of spread to neighbouring countries. As the borders are porous with substantial cross border social and economic activities, further transmission cannot be excluded. Viraemic travelling patients pose a risk for the establishment of local transmission especially in countries where adequate vectors and susceptible human populations are present.
  • Risk of establishment of local transmission in other provinces where no autochthonous cases are reported.
  • High index of suspicion of ongoing transmission in hard-to-reach areas like Cabinda.
  • Inadequate surveillance system capable of identifying new foci or areas of cases emerging.