Purification of Yellow Fever Virus Produced in Vero Cells for Inactivated Vaccine Manufacture.

Yellow fever (YF) is a high-lethality viral disease, endemic in tropical regions of South America and Africa, with a population of over 900 million people under risk. A highly effective attenuated vaccine, produced in embryonated eggs, has been used for about 80 years. However, egg-based production limits manufacturing capacity, and vaccine shortage led to the emergency use of a fractional dose (1/5) by the WHO in an outbreak in Africa in 2016 and by Brazilian authorities during an outbreak in 2018. In addition, rare but fatal adverse events of this vaccine have been reported since 2001. These two aspects make clear the need for the development of a new vaccine. In an effort to develop an inactivated YF vaccine, Bio-Manguinhos/FIOCRUZ started developing a new vaccine based on the production of the attenuated 17DD virus in serum-free conditions in Vero cells propagated in bioreactors, followed by chromatography-based purification and β-propiolactone inactivation.