Yellow fever is an acute viral haemorrhagic disease transmitted by infected mosquitoes. Most of those infected have mild illness and between 15% and 20% go into a severe haemorrhagic phase. Up to 50% of severely affected persons without proper case management will die from yellow fever. The annual estimated cases per year in at risk areas are 200 000, including 30 000 deaths. Over 900 million people are at the risk of being infected in the tropical areas of Africa and South America.
Thirty three countries in Africa are at risk of yellow fever. Those countries located between 15 latitude north and 10 latitude south. Highly endemic areas in Africa can be found in western Africa. These areas report almost annually to WHO.
Sudan is the only country in Eastern Mediterranean Region in the yellow fever zone. Large epidemics has been reported in Sudan in 1940, 1959, 2003, 2005, 2012 and 2013. Sudan conducted a yellow fever risk assessment exercise in early 2013 and confirmed that the yellow fever virus was circulating in all parts of the country. Recommendations to control yellow fever included conducting preventive vaccination campaigns, in addition to introducing the vaccine in the routine child immunization programme. Saudi Arabia requires a valid yellow fever vaccination certificate from those travelling from endemic countries to perform umrah and hajj.
Currently, a single dose of yellow fever vaccine is sufficient for life and there is no need for booster doses.