At this point no country would consider vaccinating all its children against Ebola, for example.
Of the 2,014 people who received the vaccine immediately as part of the first arm, none developed Ebola ten days after getting the vaccine. However, six days after the second group was vaccinated no new cases of the disease were found, reports NPR.
Some of the researchers involved with the study said that “they hadn’t expected such clear results”, explains Sheri Fink, a medical journalist who has been writing about Ebola for the New York Times. Previous studies showed it was safe.
Disease experts welcomed the results.
WHO vaccines expert Marie-Paule Kieny said having an effective immunization might avert future disasters but added it would still take months to get the shot approved by regulators.
YANN LIBESSART / MSF / HANDOUT/EPA A vial of an experimental Ebola vaccine proved effective against battling the immediate outbreak of the virus when tested in Guinea.
Since last year, more than 11,000 people in West Africa have died from the virus.
World Health Organization Director-General Margaret Chan addresses the media on support to Ebola affected countries, at the WHO headquarters in Geneva, September 2014.
“This is great news and the most promising medical event so far in the ongoing struggle to stop Ebola”, said the British virologist Benjamin Neumann. No instant recipients were infected, but 16 of those receiving the vaccine three weeks later were.
And the cost of mass vaccination to cover all eventualities would be prohibitive. A cluster included everyone who had been in contact with a confirmed case of Ebola, and everyone who had in turn been in contact with one of these people.
Even though health officials said the vaccine showed 100 percent effectiveness in individuals, they said more conclusive evidence is needed. “We need some type of procedure to say it’s OK to use it in these other settings”.
Draguez said his organization would start using the vaccine on health workers and was planning to encourage trials of the vaccine in Sierra Leone and Liberia.
The researchers who ran the trial say their results suggest a single injection is highly effective, and that protection against Ebola can be established quickly. She said it will affect efforts to control the current Ebola outbreak and future outbreaks. “This strategy has helped us to follow the dispersed epidemic in Guinea, and will provide a way to continue this as a public health intervention in trial mode”. It could still be awhile before the vaccine is licensed and made widely available.
The drug from Merck is one of several vaccines in clinical trials, with GlaxoSmithKline Plc and Novavax Inc. also developing medicines. Many past attempts have failed, including a recently abandoned drug being tested in West Africa by Tekmira Pharmaceuticals.
VSV-ZEBOV was developed by the Public Health Agency of Canada and is licensed to NewLink Genetics and Merck. But with case counts now down to a trickle – only seven last week – there had been fears none of the trials would come up with definitive answers.
To date, more than 4,000 participants have received the vaccine in the innovative trial, called “Ebola ça suffit” or “Ebola, that’s enough“. Plans for testing in Sierra Leone were also scaled back.