SEATTLE — In December 2015, a yellow fever breakout in Africa triggered a local and international vaccine shortage. The outbreak began in Angola and quickly overwhelmed the global emergency supply. Brazil donated 18 million doses; South Sudan contributed 400,000. Healthcare workers diluted each dose of vaccine to 20 percent of its usual concentration to fight the vaccine shortage and contain the outbreak.
Another vaccine shortage may be likely. The BBC reported last month that Brazil ordered 11.5 million doses to combat a local outbreak. Scientists are investigating 300 cases of yellow fever. They confirmed 70 cases and 40 deaths.
Yellow fever is still prevalent in Africa, Central America and South America. The disease spreads when an infected person visits a city with a high mosquito population and an unvaccinated human population. Fifteen percent of yellow fever patients experience severe symptoms associated with liver damage, including jaundice, dark urine, abdominal pain and vomiting. Half of patients with severe symptoms die within seven to 10 days.
Although an anti-viral treatment does not yet exist, the yellow fever vaccine is highly effective and is affordable at just $1 per dose. Thirty days after a single vaccination, 99 percent of patients develop immunity to yellow fever. This sets yellow fever apart from other mosquito-transmitted diseases. Zika, chikungunya and dengue don’t have effective vaccines yet.
Production may lag behind demand, however, because each batch takes six months to develop. Furthermore, manufacturers may not be able to predict the appropriate amount of vaccine to produce. The vaccine can be stored for three years, but salaries and manufacturing technology are dependent on a return on the investment. Such barriers to production contribute to a potential vaccine shortage.
The Coalition for Epidemic Preparedness Innovations (CEPI) concluded that there are “serious flaws in the world’s capacity to prepare for epidemics, and to react when they strike.” CEPI proposes “a partnership of public, private, philanthropic and civil organizations to stimulate, finance and coordinate vaccine development against priority threats, particularly when development is unlikely to occur through market incentives alone.” These efforts are primarily aimed at the production of new vaccines.
The Institute Pasteur in Dakar, Senegal plans to open another yellow fever vaccine production facility in 2020. In November 2016, the World Health Organization reported that four months passed without a case of yellow fever in Angola or the Democratic Republic of Congo.
WHO says that partners in Geneva, Switzerland are outlining a plan to eliminate yellow fever. This plan involves increasing global supplies of the yellow fever vaccine as well as “support for greater preparedness in the most at-risk countries.”
– Madeline Reding