More than 7 million Angolans have been vaccinated, but supply shortages could potentially lead to a health security crisis if yellow fever spreads within Africa, Asia (which has never experienced a yellow fever epidemic), or the Americas (where Aedes mosquito vectors transmit yellow fever as well as Zika, dengue, and chikungunya). The Pan American Health Organization declared an epidemiological alert on April 22, 2016, for yellow fever in Latin America.2 

The WHO should urgently convene an emergency committee to mobilize funds, coordinate an international response, and spearhead a surge in vaccine production. Prior delays by the WHO in convening emergency committees for the Ebola virus, and possibly the ongoing Zika epidemic, cost lives and should not be repeated.3 Acting proactively to address the evolving yellow fever epidemic is imperative.