Yellow fever vaccine supply: a possible solution

www.thelancet.com Vol 387 April 16, 2016 1599 The global threat of the emerging epidemic of yellow fever in Angola is underscored by the recent spread of similar Aedes aegypti mosquito-borne viruses including dengue, chikungunya, and now Zika. Since their emergence in the 1950s, dengue virus infection has been reported from more than 128 countries, the chikungunya virus has been reported from over 60 countries, while yellow fever, fi rst identifi ed as a viral infection in 1900, has been reported from more than 57 countries and is on the move once again. Although outbreaks of chikungunya and dengue seem to have case fatality rates of less than 1%, yellow fever outbreaks have case fatality rates as high as 75% in hospitalised cases. There has been an eff ective yellow fever vaccine since the late 1930s, but in 1987 Nigeria had an urban outbreak among an unvaccinated population that caused an estimated 120 000 infections with a case fatality rate of 20% despite a mass vaccination campaign. Presently, according to WHO, outbreaks of yellow fever are occurring in more than six of Angola’s 18 provinces, and unvaccinated travellers from Angola have arrived in neighbouring Democratic Republic of the Congo, and as far away as Kenya, Mauritania, and China. Yellow fever has heretofore never been recorded in Asia. China, India, and southeast Asian countries are considered at great risk of introduction and spread of urban yellow fever because the Aedes vector is present and the population is unvaccinated. Should yellow fever outbreaks occur elsewhere in Africa, in Latin America, or in Asia, current global supplies of yellow fever vaccine will be inadequate. A blueprint for national yellow fever contingency plans in southeast Asia had been developed in 2011 at a WHO meeting in India. In 2000, when there was a global shortage of yellow fever vaccines for outbreak response, an International Coordinating Group (ICG)—a partnership of WHO, UNICEF, Médecins Sans Frontières, and the International Federation of Red Cross and Crescent Societies—began procurement and stockpiling of yellow fever vaccine that is released to countries reporting yellow fever outbreaks based on agreed criteria for yellow fever vaccine release during outbreaks. The current global stockpile of yellow fever vaccine, however, may demand more attention. To date WHO, through the ICG, has provided 7·3 million doses of yellow fever vaccine to Angola (population about 23 million) and routine immunisation of children in those African countries that have included yellow fever vaccine in their routine childhood immunisation programmes has in some instances been suspended because of diversion of global stocks to Angola. The global supply of immediately available yellow fever vaccine from all six of the world’s manufacturers is Yellow fever vaccine supply: a possible solution *James F Cleary, Asra Husain, Martha Maurer Pain and Policy Studies Group, University of Wisconsin Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA jfcleary@wisc.edu