The Centers for Disease Control and Prevention (CDC) announced in their latest Morbidity and Mortality Weekly Report
(MMWR) that because of recent manufacturing issues, the supply of the only yellow fever vaccine licensed in the United States, YF-VAX, is expected to be completely depleted by mid-2017
However, a powerful collaborative effort between the CDC, the US Food and Drug Administration (FDA), and Sanofi Pasteur—the developer of the vaccine—is set on assuring a “continuous yellow fever vaccine supply in the United States after the anticipated complete depletion.” How? Through the implementation of an expanded access investigational new drug (eIND) protocol that will allow for the importation and distribution of “an alternative yellow fever vaccine” manufactured by Sanofi Pasteur France.
Endemic to sub-Saharan Africa and South America, humans typically get yellow fever through the bite of a mosquito infected with yellow fever virus. Although most infected individuals are asymptomatic, 15% will go on to develop severe disease; of those individuals, the case-fatality ratio can range from 20% to 50%. With outbreaks occurring in Angola, the Democratic Republic of the Congo, and more recently, Brazil
, the idea of a vaccine shortage is especially troublesome.
Currently, the live-attenuated virus vaccine, YF-VAX “produces neutralizing antibodies in 80% to 100%” of those who receive it as quickly as 10 days after reception. The CDC recommends that anyone over 9 months of age who are traveling to areas where yellow fever is endemic as they are at increased risk of infection and bringing the virus back home with them—that is how outbreaks happen. To this end, proof-of-vaccination is now required when entering specific countries.
According to the MMWR
, in 2015, a staggering 8 million individuals living in the United States traveled to 42 countries that were endemic with yellow fever. Unless these individuals received vaccination against infection, they had the potential to unknowingly, “export” the virus to non-endemic countries. In fact, between 1970 and 2013, yellow fever was reported in “at least 10” US and European travelers who were not vaccinated. Furthermore, the report states that “yellow fever virus was exported from Angola during the 2016 outbreak to three countries, with resulting local transmission in the Democratic Republic of Congo.” This fact alone emphasizes the need for travelers to be vaccinated.
Currently, in the United States, YF-VAX is the only licensed vaccine available against yellow fever. According to the report, about 500,000 doses are administered to military and civilian travelers on a yearly basis; two-thirds of these doses are given at around 4,000 civilian clinical sites.