Researchers have announced the development of an Ebola vaccine, rVSV-Zebov, that is successful in fighting one of the two major Ebola strains. According to the study, published in December 2016 in The Lancet, researchers found the vaccine to be 70-100% effective in preventing infection.¹11,841 Guineans participated in the trial to test the vaccine’s efficacy. None of the roughly 6,000 people vaccinated contracted Ebola.² Among those who were not vaccinated, 23 contracted the disease.² The vaccine was created in 2003 at the National Microbiology Laboratory in Canada, and it was subsequently developed by Merck Inc in 2014.³
The Ebola virus was first identified in 1976 in what was then Zaire. Up until 2014, roughly 1,600 lives were claimed by the disease during periodic outbreaks.⁴ Many of these smaller outbreaks occurred in remote villages and were contained by isolating the sick.⁴ However, this method alone proved to be inefficient in quelling the spread of the recent outbreak since it rapidly infiltrated densely crowded capital cities.⁴ The 2014 outbreak, which originated in Guinea and quickly spread to Sierra Leone and Liberia, claimed the lives of 11,000 people.³ Cases of the virus were also found in Europe and North America.²
The genetic makeup of the vaccine is that of a vesicular stomatitis virus, which infects cattle but does not infect humans.4 Spliced into the genetic makeup of the virus is the gene coding for an Ebola surface protein that prompts the immune system to make antibodies.⁴ It is not known if the vaccine provides long-lasting protection.⁵ Because of this, rVSV-Zebov likely will not be administered as a preventative measure (such as with the polio or smallpox vaccine) but rather as way to halt an impending outbreak.⁵
The vaccine has not yet been approved by regulatory authorities but public health officials are confident in its ability to combat the disease so much so that 300,000 doses have been stockpiled in the event of another outbreak.² The World Health Organization’s assistant director-general for Health Systems and Innovation, Marie-Paule Kieny, said the results could prove crucial to helping combat future outbreaks.⁴ "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," said Dr. Kieny.
References
Doucleff Michaeleen, “First Ebola Vaccine Likely to Stop The Next Outbreak,” NPR, Dec 22 2016, http://www.npr.org/sections/goatsandsoda/2016/12/22/506600875/first-ebola-vaccine-likely-to-stop-the-next-outbreak
“Ending Ebola: A New Vaccine is a Big Step Forward,” Chicago Tribune, Jan 20 2017, http://www.chicagotribune.com/news/opinion/editorials/ct-ebola-vaccine-who-virus-merck-lancet-edit-0121-md-20170120-story.html
Geisbert TW, "First Ebola virus vaccine to protect human beings?,” Lancet, Dec 22 2016, http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)32618-6/references
McNeil Donald Jr, “New Ebola Vaccine Gives 100 Percent Protection,” The New York Times, Dec 22 2016, https://www.nytimes.com/2016/12/22/health/ebola-vaccine.html
Mullin Emily, “Merck’s Vaccine Won’t Be the End of Ebola,” MIT Technology Review, Jan 5 2017, https://www.technologyreview.com/s/603288/mercks-vaccine-wont-be-the-end-of-ebola/