Trends over time
Yellow fever is one of the 3 diseases that are notifiable under the present International Health Regulations (IHR), adopted to ensure maximum security against the international spread of disease.
In 1948, the WHO Constitution came into force and in 1951 WHO Member States adopted the International Sanitary Regulations, which were replaced by and renamed the International Health Regulations in 1969. Although the Regulations were revised in May 2005, in this new version, yellow fever is still considered to be a public health emergency of international concern.
Under the IHR, Member States are obliged to officially notify yellow fever cases to WHO. The registration of yellow fever official cases began in 1950.
The trend in yellow fever reporting since 1950 is indicated below. Ethiopia faced a large outbreak with an estimated 100 000 cases between 1960 and 1962. Since this is an estimation, it is not included in the graph. The peaks in the graph from 1985 - 1994 are mainly due to large multipoint outbreaks in Nigeria between 1986 to 1991 (18 967 reported cases).
However, given the underreporting of yellow fever, the crude number of reported cases underestimates the real magnitude of the situation.
Recently many small outbreaks have been reported in several countries, indicating a re-emergence of yellow fever in West African countries.
The number of countries annually notifying yellow fever reflects the circulation of the yellow fever virus among human population - especially the geographical spread - and therefore the increased risk of yellow fever outbreaks.
For more information:
- The yellow fever situation in Africa and South America in 2004, Weekly Epidemiological Record. Vol. 80, 29, 2005
In a single electronic platform, the Yellow Fever Online Database brings together for analysis and comparison standardized data and statistics for yellow fever at country, regional, and global levels. The database collates the most recent epidemiological data. Relevant yellow fever data are further gathered from country-specific information on demography and vaccination coverage. This system has been developed by WHO. The database will be updated regularly to provide the latest reliable sources of epidemiological information as well as intervention coverage data for yellow fever.
Epidemiological analysis of yellow fever trends at country level gives additional information that helps to better understand the dynamic of the disease at both country and regional levels and to assess the risk of yellow fever outbreaks.
The country profiles show yellow fever trends at country level since 1950 including number of cases and deaths, vaccination coverage and details on recent outbreaks.
Angola (in French)
Benin (in French)
Burkina Faso (in French)
Burundi (in French)
Cameroon (in French)
Cape Verde (in French)
Central African Republic (in French)
Chad (in French)
Congo (in French)
Côte d'Ivoire (in French)
Democratic Republic of the Congo (in French)
Ethiopia (in French)
Gabon (in French)
Gambia (in French)
Ghana (in English) (in French)
Guinea (in French)
Guinea-Bissau (in French)
Equatorial Guinea (in French)
Kenya (in French)
Liberia (in English) (in French)
Mali (in French)
Mauritania (in French)
Niger (in French)
Nigeria (in French)
Rwanda (in French)
Sao Tome and Principe (in French)
Senegal (in French)
Sierra Leone (in French)
Sudan (in French)
Togo (in French)
Trinidad and Tobago (in French)
Somalia (in French)
Swaziland (in French)
Uganda (in French)
United Republic of Tanzania (in French)
Zimbabwe (in French)
French Guiana (in French)