How do we know the Zika virus will cost the world $3.5 billion?

The mosquito-borne Zika virus has been declared a “Public Health Emergency of International Concern” by the World Health Organization.  The virus not only appears to severely harm unborn children but is also hurting the economies of many Latin American and Caribbean countries. The World Bank estimates Zika will cost the world US$3.5 billion in 2016.

Three and a half billion dollars is a huge amount of money. How did the World Bank calculate this figure? How do we put a price tag on Zika and other health catastrophes like Ebola, dengue fever or even more common problems like the flu? Can we even trust these figures? Continue reading