The Centers for Disease Control and Prevention said this Friday that the supplies of yellow fever vaccine are expected to run out this summer. The CDC released a press statement claiming that recent manufacturing problems involving the only U.S.-licensed yellow fever vaccine will lead to a complete depletion of yellow fever vaccine available for the immunization of U.S. travelers.

The CDC said that it’s working alongside the FDA and Sanofi Pasteur to ensure a continuous supply of the vaccine. Sanofi Pasteur has submitted an application to the FDA to import an alternative yellow fever vaccine manufactured by Sanofi Pasteur France. The application was approved as the French-manufactured vaccine proved to be as effective and safe as the U.S.-licensed vaccine, and the CDC pledged to provide the public with a list of locations that will administer the replacement vaccine later in the year.

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Yellow fever is a viral disease caused by the yellow fever virus, which is transmitted to humans through the bite of a virus-carrying mosquito mostly found in sub-Saharan Africa and tropical South America. Image credit:

Yellow fever vaccine supply will run out by mid-2017

Yellow fever can be prevented by a virus vaccine that produces neutralizing antibodies in between 80 and 100 percent of vaccines by 10 days after vaccination, the CDC said. People traveling to countries located in affected areas are required to receive the vaccine, and for most travelers, only one dose is necessary. Such travelers are also required to provide a proof of vaccination when entering countries affected by the yellow fever virus. Travelers must validate their yellow fever vaccine record with a proof-of-vaccination stamp given at vaccination clinics regulated by the CDC.

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The CDC estimates that around eight million U.S. residents traveled to 42 countries with endemic yellow fever virus transmission in 2015. Image credit: Sostre SN News.

“The case-fatality ratio is 20%-50% among the approximately 15 percent of infected persons who develop severe disease,” noted the CDC in a press release. “In recent years, multiple yellow fever outbreaks in Angola, the Democratic Republic of the Congo, and, most recently, Brazil, have underscored the ongoing and substantial global burden of this disease.”

The disease can be exported by unimmunized travelers returning to countries where the virus is not present, and between 1970 and 2013 reports of yellow fever were reported from 10 unimmunized people returning to the U.S. and Europe. During a yellow fever outbreak in Angola in 2016, the virus was exported to three countries, including the Democratic Republic of Congo. The Angola outbreak caused over 965 confirmed cases from 2015 to 2017, and the current Brazil outbreak has resulted in 681 confirmed reports of the disease.

A Sanofi Pasteur-manufactured vaccine called YF-VAX is the only vaccine licensed for use in the U.S. The CDC said that 500,000 doses are distributed each year to vaccinate military and civilian travelers and that over two-thirds of the doses are distributed among over 4,000 civilian clinical sites.

The CDC will soon say which clinics are eligible for replacement yellow fever vaccine

The current vaccine depletion began in November 2015, as Sanofi Pasteur was moving production of the vaccine to a newer facility set to open in 2018. However, a manufacturing complication caused the loss of a large number of doses, and in 2016 Sanofi Pasteur notified the CDC of a probable complete depletion of the yellow fever vaccine later that year. The company was capable of producing more inventory, but it will run out by mid 2017.

At that time, the CDC, Sanofi Pasteur, the FDA, and the U.S. Department of Defense sat down to discuss the yellow fever vaccine depletion. They considered using a fractional yellow fever vaccine dosing, but it was quickly deemed a nonviable option as it would not be as effective.

The CDC noted that they’ve worked with Sanofi Pasteur to assure a continuous yellow fever vaccine supply after the anticipated complete depletion of YF-VAX in summer 2017. Image credit: Biopharma Reporter.

Ultimately, Sanofi Pasteur submitted an eIND (expanded access investigational new drug) application to the FDA for U.S. importation and civilian use of Stamaril, a yellow fever vaccine manufactured by Sanofi Pasteur France. As Stamaril is not licensed in the U.S. -but it’s proven to be as effective as YF-VAX- the Department of Defense submitted its own eIND application too, and the FDA approved Sanofi Pasteur’s eIND in October 2016.

The CDC cautions future travelers who need the shot, that accessing the vaccine may be difficult in the months to come, as Stamaril will only be distributed to 250 clinics, as opposed to the regular 4,000 clinics that provide yellow fever vaccination. The organization will notify state and territorial health department immunization programs about Stamaril, and information about which clinics are eligible to receive Stamaril will be released soon.

Source: CDC