An Ebola jab is being given to people living in the West African areas hit most by the virus after human trials in unaffected countries proved successful.
Scientists hope immunisation is possible with just one injection after “highly promising results” in the first 138 healthy adults who were vaccinated with various doses.
The vaccine, developed in Canada, is based on an animal virus called vesicular stomatitis virus (VSV) that is combined with a portion of the protein covering of the Ebola virus. When administered, it induces an immune response against the Ebola virus.
The researchers whose findings are published in the New England Journal of Medicine said one jab protects against a disease which has killed more than more than 10,460 people in a year across six countries including Liberia, Guinea, Sierra Leone, Nigeria, the US and Mali.
Dr Michael Ramharter, of the Medical Research Unit at Albert Schweitzer Hospital, Lambarene, Gabon, said the Ebola antigen is inserted into the vaccine as a Trojan horse to get the body to develop an immune response against the virus.
He explained: “An Ebola glycoprotein from the Ebola strain in Zaire is being inserted into the VSV live vaccine. While VSV only causes mild symptoms in humans, the protein acts as an Ebola antigen and triggers the formation of antibodies against the disease in the immune system.”
Dr Ramharter said these antibodies hide, almost like a ‘Trojan horse’, in the body in order to successfully fight the Ebola virus if the individual becomes infected.
He added: “Just one vaccine has conferred one hundred per cent protection against Ebola in the initial trials on primates.”
Dr Ramharter said the first phase I clinical trial is now complete and the results are “highly promising”.
He said: “The vaccine response is very reliable, the vaccine itself is safe and its tolerability is acceptable.”
The most significant side effect was found to be temporary joint pain and inflammation reported among a small group of test subjects, particularly in the European centres.
In the phase II studies that are now beginning, the vaccine will be used in patients living in the areas currently most badly affected by Ebola, especially Guinea and Sierra Leone, but also in Liberia.
The first case of Ebola was reported in West Africa around 15 months ago. According to estimates, around 25,000 people have been infected by the virus, with more than 10,000 of them having died since as a result.
The race is on to find ways to prevent and cure the Ebola virus as there are no proven treatments or vaccines to prevent individuals becoming infected.
But progress is now being made on an unprecedented scale with trials which would normally take years and decades being fast tracked on a timescale of weeks and months.
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The aim is to use the lowest dose of vaccine possible that provides protection. Vaccines train the immune systems of healthy people to fight off any future infection.
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