Yellow Fever Vaccine Administration at Global TravEpiNet (GTEN) Clinics during a Period of Limited Vaccine Availability in the United States, 2017-2018

Abstract

In 2016, Sanofi Pasteur (S-P) experienced a manufacturing disruption of YF-Vax, the only U.S.-licensed yellow fever vaccine depleting the U.S. supply by mid-2017. Sanofi Pasteur received approval to import Stamaril, S-P's French-manufactured yellow fever vaccine, for use in 260 U.S. civilian clinics under an Expanded Access Program (EAP). The CDC also broadened its yellow fever vaccination indication in early 2018. Our objective was to assess usage at participating Global TravEpiNet (GTEN) clinics, a U.S. CDC-supported national consortium of clinical sites that administer vaccines, during this period of limited availability and changing recommendations. We analyzed 2012-2018 GTEN data for yellow fever vaccine usage, unavailability, and reasons for refusal. We also performed a brief voluntary survey of GTEN sites to better understand their experience during the shortage. YF-Vax unavailability at certain GTEN clinics was intermittent and recurrent, starting months before total depletion. Unavailability at GTEN clinics peaked weeks before the total depletion. Compared with historic norms, yellow fever vaccine usage following initial vaccine availability limitations did not change until vaccine recommendations were broadened. Refusal of recommended yellow fever vaccine also decreased during this period. Queried sites participating in the EAP felt their supply of vaccine was adequate. Our analysis suggests that in response to depletion of a travel vaccine, an EAP can make an unlicensed product available, patients will participate in such a program, and the program can respond to expanding recommendations for vaccine usage.

Figure 1.

(A) Total number of yellow fever vaccines (YF-Vax and Stamaril) administered at Global TravEpiNet (GTEN) sites by week per year, 2012–2018. Hatched arrow: EAP began filling orders. Black arrow: Total manufacturer depletion of YF-Vax. Open arrow: CDC broadened indications for vaccination against yellow fever virus for travelers to Brazil. (B) Percentage of total GTEN clinic visits where yellow fever vaccines (YF-Vax and Stamaril) were administered by week per year, 2012–2018. Hatched arrow: EAP began filling orders. Black arrow: Total manufacturer depletion of YF-Vax. Open arrow: CDC broadened indications for vaccination against yellow fever virus for travelers to Brazil.

Figure 2.

Total number of yellow fever vaccines (YF-Vax and Stamaril) administered to travelers to Brazil at Global TravEpiNet sites by week per year, 2012–2018. Hatched arrow: EAP began filling orders. Black arrow: Total manufacturer depletion of YF-Vax. Open arrow: CDC broadened indications for vaccination against yellow fever virus for travelers to Brazil.

Figure 3.

Total number of times a yellow fever vaccine (YF-Vax or Stamaril) was deemed indicated by a clinician, but yellow fever vaccine (YF-Vax or Stamaril) was not available at Global TravEpiNet sites by week per year, 2012–2018. Hatched arrow: EAP began filling orders. Black arrow: Total manufacturer depletion of YF-Vax. Open arrow: CDC broadened indications for vaccination against yellow fever virus for travelers to Brazil.

Figure 4.

Yellow fever vaccine (YF-Vax or Stamaril) yearly usage data at Global TravEpiNet sites (2012–2018) by proportion for travelers to countries any part of which were endemic for yellow fever by month per year. Usage categories: yellow fever vaccine administered during the encounter; the traveler had pre-existing immunity; yellow fever vaccine was indicated but there was a medical contraindication to administering the vaccine; the traveler declined vaccination; the travel was to a region of the country not endemic for yellow fever and vaccination was not indicated for that itinerary; or yellow fever vaccine was not available; or other (for instance, itinerary was not yet established, and traveler asked to return to the clinic at future date). This figure appears in color at www.ajtmh.org.