According to an unusual new study, published last week in the world’s most prestigious medical journal Lancet, the deadly outbreak of the Ebola virus, which has been devastating West Africa for more than 18 months now, might finally come to an end – a vaccine, developed by the Public Health Agency of Canada and manufactured by the American pharmaceutical company Merck Sharp & Dome, was just shown to confer 100% protection against the disease, starting mere 10 days after receiving a single shot.
“This will go down in history as one of those hallmark public health efforts,” said Michael Osterholm, Director of the Center for Infectious Disease Research and Policy in Twin Cities, Minnesota, who wasn’t involved in the study. “We will teach about this in public health schools.”
The vaccine, which consists of the Vesicular Stomatitis Virus (pathogenic in livestock, but harmless in humans) with the Ebola surface protein stitched onto it, was greenlit for a trial in October, but got off the ground only in March, when cases already begun to plummet and were scattered across a large area in Guinea.
Unable to enrol enough people to demonstrate efficacy in a standard randomized trial, the researchers opted for a design called ring vaccination, whereby only the contacts, and the contacts’ contacts, of new Ebola patients were vaccinated. This type of approach has never been used in a formal vaccine study ever before.
The rings, also called clusters, were randomized such that 48 of them received the vaccine right after a new Ebola case sprung up in their community, while the other 42 received a shot only three weeks afterwards.
Of the 2,380 people who were assigned to the latter group, 16 got infected. In the second group – consisting of 2,014 people – the count of new Ebola cases was zero, which (at least in the context of this study) translates to 100% efficiency.
In fact, the outcome was so convincing, that the independent group, watching over the safety of study participants, recommended to start vaccinating all of the clusters immediately, which the researchers have now started doing.
The Director-General of the WHO Margaret Chan called for further studies to clear up any lingering doubts about the vaccine’s efficacy, but was hopeful it will soon prove to be a game-changer in managing both the current and possible future outbreaks of the virus.
Experts have also noted that while current statistics on the epidemic are the most promising in well over a year – last week, only four new cases were observed in Guinea and three in Sierra Leone – the virus could easily flare up again.