By Jennifer Lazuta | From Voice of America

Angola is battling a yellow fever outbreak amid a global shortage of the vaccine. Cases have also been reported in the Democratic Republic of Congo, Kenya, Uganda and China. Health experts worry about further spread. There is no treatment. Mass immunization is the only way to stop yellow fever, but producing more of the vaccine is not easy.

Making of a vaccine

The Institut Pasteur de Dakar is one of four places in the world that make the yellow fever vaccine.

Recording is prohibited inside the institute, but there is nothing to hear. The halls are quiet. Two walls of windows separate us from the sterile labs where technicians work in head-to-toe protective gear.

Each week, a carton of special, pathogen-free chicken eggs arrives from Germany. Technicians inject the embryos, one by one, with the live virus. That’s a first step. What follows is weeks of extraction, mixing, incubation and safety checks.

It can take up to six months to produce a batch of usable vaccine.

Globally, around 80 million doses of yellow fever vaccine are made each year. The Institut Pasteur can produce up to 10 million doses.

Meeting global needs

Antoine Marie Diatta is the quality control manager for yellow fever vaccine production at the institute. He said unfortunately our production capacity can’t always meet the global needs. It’s the same for other manufacturers, he said. This can be a problem when there is an epidemic, he said, because then there is an immediate need to vaccinate a large number of people.

It can be hard to predict how much vaccine will be needed.

Yellow fever vaccines can be stored for up to three years, but manufacturers can’t afford to over produce, as Diatta explained.

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