Experimental Ebola vaccine tested on humans found safe
New Delhi,June19: Declared an epidemic and a global emergency by the World Health Organisation, the deadly Ebola virus held West Africa hostage from 2013-2016.
It was the most widespread outbreak of Ebola virus disease (EVD) in history and resulted in major loss of life and socio-economic disruption in the region, mainly in the countries of Guinea, Liberia, and Sierra Leone.
In December 2016, an experimental Ebola vaccine tested on humans in the waning days of the West African epidemic had shown 100 percent protection against the lethal disease, while in March 2017, an early human trial revealed that a two-part Ebola vaccine regimen has been found to offer protection against the deadly disease for about a year.
The study found that the recombinant vesicular stomatitis virus-Zaire Ebola virus (rVSV-ZEBOV) is well-tolerated and showed no safety concerns.The rVSV-ZEBOV is a recombinant, replication competent vesicular stomatitis virus-based candidate vaccine expressing a surface glycoprotein of Zaire Ebola virus.Only mild to moderate side-effects were seen, with only three severe reactions, including headache, diarrhoea and fatigue, which were completely resolved, the researchers said.Further, participants reported high-antibody levels in six months after the immunisation.
“The results of this trial were positive and very promising. All three dose levels of the rVSV Ebola vaccine were well-tolerated by participants, and no safety concerns were identified,” said lead author May ElSherif, Canadian Centre for Vaccinology – an integrated collaborative vaccine research centre in Nova Scotia.
Data from this trial and others indicated an optimum dose of 20 million plaque-forming unit (PFU) that will be assessed among people with compromised immune systems in areas where Ebola is endemic.
There were some latest clusters of Ebola cases in Africa and more expected as survivors may still spread the virus to uninfected people, the researchers said.
For the trial, published in CMAJ (Canadian Medical Association Journal), the team involved 40 healthy people aged 18 to 65 years and looked at safety of the vaccine and the lowest dose required for an immune response after injection with one of three doses.
Given the ongoing presence of Ebola, “these facts underscore the importance of continuing efforts and collaborations that may ultimately lead to licensed Ebola vaccines that would protect humans and prevent or control outbreaks in the future,” ElSherif added.