The experimental vaccine ― which has not yet been approved by any regulatory authority ― has already completed successful trials in Sierra Leone and Guinea, among the hardest hit countries during the epidemic. Not a single subject given the vaccine developed Ebola, according to research published in The Lancet by scientists from the World Health Organization, the Norwegian Institute of Public Health and other groups.
The news comes just a couple years after a 2014 epidemic in West Africa killed more than 11,000 people, including one in the United States and several in Europe.
“While these compelling results come too late for those who lost their lives during west Africa’s Ebola epidemic, they show that when the next Ebola outbreak hits, we will not be defenseless,” Marie-Paule Kieny, the WHO’s assistant director general for health systems and innovation and the study’s lead author, told The Guardian.
The creation of such an effective vaccine in near light speed is “remarkable,” scientists say, and an emergency stockpile of 300,000 doses has been created in case of another outbreak, The New York Times reports.
But while the vaccine had 100 percent efficacy among the nearly 6,000 test subjects in Guinea who received it, NPR notes those numbers will likely decline over time as more people are vaccinated, and more work is likely needed to craft a “perfect” counter to the virus.
Scientists are also unsure about its long-term effectiveness and have pointed to some side troublesome side effects like headaches and muscle pain. The experimental vaccine (dubbed rVSV-ZEBOV) may also only protect against one of the two common Ebola strains, which will mandate continued work to fully prevent the virus, according to the Times.
The Ebola outbreak in 2014 sparked a global health emergency as officials scrambled to contain the virus as it debilitated entire countries in West Africa. It was the largest such outbreak in history.
Researchers working on the crisis wrote the outbreak was “clearly not the ideal situation for doing a vaccine trial,” but urgent international need for a solution helped spur work with local government to establish an effective method “in compliance with good clinical practice and international standards.”
The vaccine has yet to be approved by a regulatory agency like the Food and Drug Administration. But its manufacturer, Merck, Sharp & Dohme, has been given permission to go through fast-track procedures to meet those hurdles, according to The Guardian.