WHO Director-General Warns Not to Ignore Threat of Yellow Fever

Updated June 6, 2016 at 11:06 EST

In an address to the 69th annual World Health Assembly, Margaret Chan, MD, MPH, director-general of the World Health Organization (WHO), discussed the impending threat of yellow fever.

Dr. Chan began her address by acknowledging how “commitment to the Millennium Development Goals brought focus, energy, creative innovation, and above all money to bear on some of the biggest health challenges that marred the start of this century.” She called on health officials from around the world to celebrate the large drop in mortality rates from a number of serious causes, such as child labor, tuberculosis, and malaria. She then went on to discuss the transnational nature of infectious diseases, citing illnesses such as those arising from food-borne infections, as well as Ebola, Zika, and yellow fever. Dr. Chan stated, “In an interconnected world characterized by profound mobility of people and goods, few threats to health are local anymore.”

Dr. Chan stated that the rise of yellow fever in the cities of Angola and the Democratic Republic of Congo is a serious issue that should not be ignored, further noting that “yellow fever is not a mild disease.” The director-general went on to criticize the approach used to fight yellow fever. She stated that the rate of urbanization of African countries has been rapid and uncontrolled, noting that WHO has been warning African countries for more than a decade that demographic changes, as well as varying land use patterns will create “ideal conditions for explosive outbreaks of urban yellow fever.” Dr. Chan stated that rural migrants, as well as mining and construction site workers, transport the virus to these urban regions, causing serious consequences. “Dense populations of non-immune people, heavy infestation with mosquitoes exquisitely adapted to urban life, and the flimsy infrastructures that make mosquito control nearly impossible,” all contribute to the rapid spread of the disease.

In a recent study published in the Journal of the American Medical Association, Daniel Lucey, MD, MPH, and Lawrence O. Gostin, JD, warned that yellow fever can be the next global health crisis, calling on WHO to take action. Although there is an effective vaccine against yellow fever, the waning supply will not suffice in the case of an international epidemic. The authors suggested that WHO declare a global health emergency and set a plan to lower the dose of vaccination to extend the supply.

Additionally, there isn’t just one group of researchers that raises concern of the imminent threat of yellow fever. In a more recent study published in the International Journal of Infectious Diseases, authors stated that an outbreak in unvaccinated populations strengthens the possibility of epidemics in Africa as well as in Asia, where a recently documented case in China was the first ever reported on the continent. As of May 25, 2016, there have been 747 lab confirmed cases of yellow fever and 301 related deaths in Angola alone.

Commenting on the outlook of yellow fever infection rates, Dr. Chan stated that the disease has the potential to spread internationally across the globe. “Yellow fever vaccines should be and must be used more widely to protect people living in endemic countries,” she urged.

In this year’s annual report on the implementation of the International Health Regulations, it was stated that a resolution adopted in the 67th World Health Assembly, which updated the period of effectiveness of the yellow fever vaccine from 10 years from the date of vaccination to life, would be implemented in July 2016. Furthermore, in response to a request posed by the 68th World Health Assembly, Dr. Chan “established a scientific and technical advisory board to map the risk of yellow fever and provide guidance on vaccination for travelers” and will be publishing an “an updated online list of countries that accept a certificate of vaccination against yellow fever for life.”

In response to the threat of a global health crisis that may be caused by yellow fever and other infectious diseases, Dr. Chan urged decision makers to take a stance. “WHO is the organization with universal legitimacy to implement the International Health Regulations [IHR]. The evaluations must be accompanied by well-resourced efforts to fill the gaps. Many generous countries have promised to support 76 countries to build IHR core capacities. I urge you to keep this promise,” she stated.

In a world where international travel is no longer considered a ‘phenomenon,’ neither should international transmission of infectious diseases, since political borders cannot contain an outbreak. Yellow fever is spread through the bite of either an infected Haemagogus mosquito or an infected Aedes mosquito, and one unreported case is all it takes to spread the disease among an uninfected population.