Ebola Vaccine Offers 100% Protection Against Deadly Virus

An experimental vaccine manufactured by Merck, Sharpe, and Dohme is showing 100% effectiveness against the Ebola virus, according to results of a trial conducted in Guinea; yesterday, the results were published in The Lancet.

In the World Health Organization’s press release, the study’s lead author Marie-Paule Kieny, PhD, WHO’s Assistant Director-General for Health Systems and Innovation, said, “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.”

Researchers hope that this vaccine will be the answer to ensuring that any future outbreaks will not be of the same levity as the devastation that was the 2013-2016 West African Ebola outbreak, an outbreak that claimed over 11,300 lives.

In the trial, named “Ebola Ça Suffit!,” the vaccine was tested on individuals in West Africa—Basse-Guinèe, Guinea—between March 23, 2015 and January 20, 2016. Although it has not yet been approved by the US Food and Drug Administration or any other agency, it is considered so effective than an emergency stockpile of 300,000 doses has already been created should there be another outbreak, the New York Times reported.

According to The Lancet study, the vaccine, called rVSV-ZEBOV is a recombinant replication competent vesicular stomatitis virus-based vaccine that expresses a surface glycoprotein of the Zaire strain of Ebola virus. It was given in a single intramuscular dose administered in the deltoid muscle. The trial used the same method that researchers previously used to eradicate small pox: a “ring vaccination” approach; this means that researchers vaccinated known contacts of individuals with newly diagnosed Ebola infection—anyone who had been in contact with that newly infected individual within the three weeks prior to infection. The researchers found that there were 117 “rings,” or clusters of these “contacts,” each cluster comprised of 80 people on average. Some were vaccinated immediately, while others were not vaccinated until after a “3-week delay.” In all, 2,151 people were vaccinated. The researchers found that “no cases of Ebola virus disease occurred 10 days or more after randomization.”

Furthermore, individuals who were not vaccinated were still protected from the deadly virus through the innovative “ring vaccination” approach. However, according to the press release, “the trial was not designed to measure this effect, so more research will be needed.”

According to Sakoba KeÏta, coordinator of the Ebola Response and director of the National Agency for Health Security in Guinea, “Ebola left a devastating legacy in our country. We are proud that we have been able to contribute to developing a vaccine that will prevent other nations from enduring what we endured.”

Funding was provided by WHO, the UK Wellcome Trust, Médecins Sans Frontières, Norwegian Ministry of Foreign Affairs (through the Research Council of Norway's GLOBVAC programme), and the Canadian Government (through the Public Health Agency of Canada, Canadian Institutes of Health Research, International Development Research Centre and Department of Foreign Affairs, Trade and Development).