With an eye on the spread of the disease through Angola, Dr, Lucey shared that investigators recommended the use of one-fifth or even one-tenth of the regular dose of the regular vaccine just in case of shortage (The study
was published in the Lancet
.) Following that, he also spoke about an article
that he co-authored, published in the Journal of American Medicine,
that further anticipated a vaccine shortage, especially if the disease spread to Asia. “What we were very worried about actually, unfortunately, came to pass,” Dr. Lucey said. “A yellow fever vaccine shortage in the face of a yellow fever epidemic in Angola.”
When this happened in Kinshasa in July and August of 2016, health officials from all different international organizations came together for a “valiant” vaccination effort, in which they administered one-fifth, or 20% of a regular dose of vaccine to upwards of 7 million individuals; this was the first time that a fractional dose had ever been given in a mass vaccination campaign and, consequentially, had succeeded in stopping an epidemic. The question remains though—how long does immunity against the disease last with a fractioned dose?
The answer to this question could have “very important implications” Dr. Lucey explained. "If there had been one other city, if the virus had crossed over to Brazzaville (which is within eyesight of Kinshasa), then there probably wouldn't have been enough vaccine to give full dosing, so it would have to have been reduced dosing."
He stated that 3 small studies published in the past thought the answer to be 12 months. “[The authors] stated that probably immunity after a one-fifth dose lasts for longer than 1 year, but it’s never been studied,” he said.
Following the successful vaccination campaign— “the first of its kind, ever, in history”—a World Health Organization (WHO) committee met again to create the Global Strategy to Eliminate Yellow Fever Epidemics (EYE
), a ten-year plan, ranging from 2016 to 2026. The plan is to “create all together a stockpile of yellow fever vaccine: it’s estimated that about 1.38 billion doses would be necessary to eliminate yellow fever from sub-Saharan Africa and Latin America,” Dr. Lucey explained. Although WHO recognized the potential of Asia falling victim to an epidemic, there is no vaccine stockpiling plan in place for the continent. “In the moderate to a longer-term time frame, that could become a focus for emphasis,” Dr. Lucey said. “In my view, it should be emphasis now, in the short-term.”
He also highlighted the “unanticipated and fairly large” outbreak that sprung up in Brazil, an outbreak that spread “right up to the edge of several large cities, include Rio de Janeiro and San Paulo.” At the same time, Brazil was experiencing a yellow fever vaccine shortage. “Brazil produces more yellow fever vaccine, to my knowledge than any other country in the world,” Dr. Lucey shared. Despite this, they still had to import 3.5 million doses from the global stockpile to fight the outbreak, which consists of 798 lab-confirmed cases and over 2000 suspected cases thus far. “There’s no urban transmission, and there hasn’t been in many decades in Brazil but we came very, very close,” he stressed. “And if it had reached the cities, then I think the issue would have been brought up again: if there’s not enough vaccine, then use reduced doses of yellow fever vaccine for people within the cities.”