To head off an impending shortage of YF-VAX, the only US-licensed vaccine for yellow fever, Sanofi Pasteur, the US Centers for Disease Control and Prevention (CDC) and the US Food and Drug Administration (FDA) are working to provide travelers with an alternative vaccine.
In the coming months, Sanofi will begin importing Stamaril, a yellow fever vaccine developed from the same substrain as YF-VAC, and will distribute it to select clinics around the US.
While Stamaril is considered investigational by FDA, CDC says the vaccine "is not investigational or experimental," and has comparable safety and efficacy to YF-VAX. CDC also notes that Stamaril has been in use since the mid-1980s and is approved in 70 countries around the world, including much of Europe.
Yellow Fever: Background and Shortage
Yellow fever is a potentially life-threatening viral disease typically transmitted to people by mosquitoes and is prevalent in sub-Saharan Africa and South America. Recent outbreaks in Angola, the Democratic Republic of the Congo, Uganda and Brazil have prompted the World Health Organization (WHO) to launch mass-vaccination campaigns in those countries.
While yellow fever is not found in the US, CDC recommends that people nine-months or older traveling to areas where the disease is transmitted get vaccinated prior to travel.
According to unpublished data from Sanofi, roughly 500,000 doses of YF-VAX are distributed to some 4,000 CDC-designated clinics and the US military each year.
While Sanofi had planned to have enough doses of YF-VAX to last through its transition to a new manufacturing facility set to open in 2018, a "manufacturing complication" led to the loss of a large portion of its inventory and sparked the impending shortage.
Despite measures to limit orders and the production of additional doses of the vaccine late last year, Sanofi says it expects supplies of YF-VAX to be depleted sometime in mid-2017.
In order to provide Stamaril to patients in the US, Sanofi submitted an expanded access investigational new drug application (eIND) to FDA in September 2016 that FDA accepted the following month.
While FDA's expanded access program is more widely known as an avenue for patients with serious or immediately life-threatening diseases to get access to unapproved treatments outside a clinical trial, the agency has used expanded access in the past to provide access to a vaccine.
In 2013, meningitis B outbreaks at Princeton University and the University of California, Santa Barbara prompted CDC to submit an eIND to FDA to allow the importation and use of Novartis' Bexsero at those campuses. According to FDA, more than 15,000 students were vaccinated under the program.
Under the eIND, Stamaril will only be distributed to selected sites in the US based on criteria developed by Sanofi in consultation with CDC.
Tier 1 sites will be selected based on the volume of yellow fever vaccine the sites ordered in 2016, with additional sites being selected to ensure that all 50 states and the District of Columbia, Guam, Puerto Rico and the US Virgin Islands have at least one site providing Stamaril. Tier 2 sites will include multi-site clinical organizations that ordered at least 250 doses of yellow fever vaccine across all their sites in 2016.
So far, CDC says that 250 sites have been identified, and that Sanofi is actively working to recruit sites to participate in the protocol, a sizable reduction from the 4,000 sites currently designated to provide YF-VAX.
While CDC says it and Sanofi will "monitor for critical gaps in vaccine access," the agency predicts that some travelers may have difficulty accessing the vaccine due to the narrower distribution.
According to Sanofi, the importing the necessary singe-dose vials of Stamaril into the US for use under the eIND should not have a large impact on the supply of the vaccine globally.