Ebola Vaccine tested on the monkeys in Bethesda in Washington, United States on November 22, 2000. [Getty Images]

UNITED STATES - NOVEMBER 22: Ebola Vaccine tested on the monkeys in Bethesda in Washington, United States on November 22, 2000 - Preparation of plates of growth medium liquid in order to test the expected expression of proteins by the two Ebola vaccines. (Photo by Raphael GAILLARDE/Gamma-Rapho via Getty Images)

Gamma-Rapho Raphael GAILLARDE