Ebola vaccine proves effective, final trial results show

An experimental Ebola vaccine has triumphed in West Africa.

Of 5,837 people in Guinea who received a single shot of the vaccine, rVSV-ZEBOV, in the shoulder, none became infected with the virus 10 to 84 days after vaccination. That’s “100% protection,” researchers report December 22 in the Lancet.

World Health Organization researcher Ana Maria Henao-Restrepo and colleagues tested a “ring vaccination” approach, by immediately vaccinating family members and other contacts of people infected with Ebola. This strategy seemed to staunch the virus’s spread. Among 4,507 people never vaccinated or who got a delayed vaccine, 23 contracted Ebola.

The findings echo preliminary results reported in 2015, and offer a promising line of defense for future outbreaks. But scientists still do not know how long-lasting the vaccine’s protection would be.

In late 2013, West Africa saw the beginning of what would become the largest Ebola outbreak in history, with more than 11,300 deaths reported, and 28,616 cases in Guinea, Sierra Leone and Liberia. Since then, scientists have been racing to create a safe and effective vaccine.