Another pandemic disaster looms: yellow fever spreading from Angola

Abstract

For more than a decade, WHO has been warning that changes in demography and land use patterns in Africa have created ideal conditions for explosive outbreaks of urban yellow fever (YF). Africa's urbanization has been rapid and rampant, showing the fastest growth rates anywhere in the world. And for more than a decade, some of us in public health have been concerned about the increasing threat of the introduction of YF into Asia. But during all that time, market forces have kept the supply of YF vaccine below global demand. But nobody foresaw the emergence of urban YF in a low-risk country like Angola, nor of viremic people taking it from there to Kinshasa, capital of the Congo DR, and even China, the first time YF has ever been reported in Asia. Every country that has dengue, carried by the same Aedes mosquitoes that spread YF, is now at risk. Mosquito control has not succeeded in controlling dengue anywhere, so will be unable alone to stop a pandemic. The only immediately available preventive measure is the vaccine. But there is not enough vaccine available from manufacturers` stocks now, nor that can be produced in the coming months with current capacity. Increasing production rapidly is problematic. Figures for cases and deaths are probably underestimates by a factor of 10, according to WHO`s own expert after a visit in March, so that two months ago there were already thousands of cases and many hundreds of deaths. Angola has a population of at least 24 million, so another 16 million doses of vaccine are needed for enough coverage to bring the epidemic to an end. Now global stocks will soon be exhausted unless steps are taken immediately to conserve vaccine by authorizing the use of a lower, but still effective, 1/5th dose.