A new Ebola vaccine is being called “highly effective” following a small study in Guinea, West Africa.
“After a poorly managed global response to the Ebola outbreak last year, news of the phenomenal successes of these vaccine trials in Guinea-100% efficacy in a trial cohort of 4,000 patients-is simply tremendous”, said Michael Weinstein, President of AIDS Healthcare Foundation.
“But this is a first ray of hope: an effective vaccine could be a game changer and finally put an end to the outbreak, which is still not under control in West Africa”, Dr. Joanne Liu of Doctors Without Borders said on Facebook.
The experimental vaccine VSV-ZEBOV was found to be 100% effective six days after it was administered to 7,651 people living in Guinea, where the virus has already claimed more than 2,500 lives.
The Lancet, in an editorial accompanying the study, called the result a “remarkable scientific and logistical achievement”.
Comparisons between an active and “dummy” placebo vaccine could not be made for ethical reasons, since it would have meant condemning one group of participants to a high risk of death. To make the vaccine, the vesicular stomatitis virus was weakened by removing one of its genes, which was then replaced with a single Ebola virus gene that can not cause disease by itself. At the moment Guinea and Sierra Leone are the only two countries recording cases of Ebola. The randomization was stopped on Sunday “to allow for all people at risk to receive the vaccine immediately, and to minimize the time necessary to gather more conclusive evidence needed for eventual licensure of the product”, the WHO said.
A number of other groups are at an earlier stage of research, including a team from the University of Texas working on an inhaled vaccine.
It combined a fragment of the Ebola virus with another safer virus in order to train the immune system to beat Ebola.
His excitement was shared by the scientist who headed the project to develop the vaccine, Dr. Heinz Feldmann, who struggled for years to try to find a way to prove that the vaccine would work as well in people as it does in non-human primates.
Draguez and other experts are heartened by the new results – but they also warn that as testing expands, the effectiveness rate of the vaccine will likely fall below 100 percent.
Studies in non-human primates suggest a vaccine that protects against Ebola Zaire won’t protect against the Sudan or Bundibugyo strains, and vice versa.
The trial is being implemented by the Guinean authorities, WHO, Médecins Sans Frontières (MSF) and the Norwegian Institute of Public Health, with support from a broad partnership of worldwide and national organizations. In late 2014, Merck licensed the vaccine from NewLink Genetics to apply Merck’s vaccine expertise to help accelerate the development of this promising candidate.
A man gets vaccinated on 10 March 2015 at a health centre in Conakry, Guinea.
Such “rings” of vaccination took place either immediately after an Ebola infection was confirmed or three weeks later, according to the researchers’ random assignments.
This trial centred on the VSV-EBOV vaccine, which was started by the Public Health Agency of Canada and then developed by the pharmaceutical company Merck. The report also said the organization plans to work to improve its communication and cultural engagement strategies.
