In a scientific triumph that will change the way the world fights a killer, an experimental Ebola vaccine tested on humans in the waning days of the West African epidemic has been shown to provide 100 percent protection against the lethal disease.
The vaccine has not yet been approved by any regulatory authority, but it is considered so effective that an emergency stockpile of 300,000 doses has been created for use should an outbreak flare up again.
Since Ebola was discovered in the former Zaire in 1976, there have been many efforts to create a vaccine. All began with a sense of urgency but then petered out for lack of money. Although only about 1,600 people died of Ebola over those years, the grotesque nature of their deaths has lent the disease a frightening reputation.
Ultimately, only the explosive 2014 outbreak that took 11,000 lives in Africa and spread overseas, killing a handful of people in Europe and the United States, provided the political and economic drive to make an effective vaccine.
The test results of the trial in Guinea were released Thursday in The Lancet.
The vaccine was not ready in time to stop the outbreak, which probably began in a hollow, bat-filled tree in Guinea and swept Liberia and Guinea before being defeated. But the prospect of a vaccine stockpile has brought optimism among public health experts.
The vaccine opens up new, faster, more efficient ways to encircle and strangle the virus. .
The new vaccine has some flaws, experts said. It appears to work against only one of the two most common strains of the Ebola virus, and it may not give long-lasting protection. Some of those who get it report side effects like joint pain and headaches.
The Lancet study was done in 11,841 residents of Guinea last year. Among the 5,837 people who got the vaccine, none came down with Ebola 10 or more days later. There were 23 Ebola cases among the thousands of others not immediately vaccinated.