Ebola vaccine from Canada seems to work in trial in Guinea: WHO

Theexperimental Ebola vaccine designed by Canadian scientistsseems to work, the interim results of a trial in Guinea suggest.

If proven effective, the vaccine could be "a gamechanger," said Dr. Margaret Chan, directorgeneral of the World Health Organization, which sponsored the trial.

The interim findings were publishedonline Friday in the medical journalThe Lancet.

The findings so far are persuasive, Dr.Marie-PauleKieny, a senior author of thetrial, told reporters from Geneva.

"The data so far shows that none of the 2,014 persons vaccinated developed Ebola virus disease after 10 days after vaccination," saidKieny, whooversees research and development related to Ebola at WHO.

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The search for a vaccine was spurred by the current Ebola outbreak inWest Africa , which has killed more than 11,000 people inGuinea, Sierra Leone and Liberia sincetheepidemic began in Guinea in December 2013.

The vaccine, known as rVSV-ZEBOV, wastested onmore than 4,000 peoplewho had been in close contact with a confirmed Ebola case in Guinea.

Of those who received the vaccine within 10 days of being identified as an Ebola contact, there were no cases of the disease. That compared with 16 cases in more than 3,500 people who received the the shot after 10 days.

"It suggests it works, it works pretty quicklyand it workswell," saidKieny.

More conclusive evidence is needed andtrials will continue,WHO tweeted.

Dr. Joanne Liu, international president of Doctors Without Borders, said more research is needed to understand exactly how the vaccine protects and how long the protection lasts.

"But this is a first ray of hope: an effective vaccine could be a game changer to finally put an end to the outbreak which is still not under control in West Africa," Liu said on Facebook.

In a "ring vaccination trial,"rings of contacts around Ebola cases are identifiedand randomly vaccinated eitherimmediately or after 21 days. The time lag avoids the need to use a placebo.

Doctors used the same strategy of vaccinating those at greatest risk first to eradicate smallpox in the 1970s.

'Amazing accomplishment'

Given the positive results,Kieny told reporters that thedelayed vaccination arm of trial will end and allcontacts will bevaccinatedimmediately. Children and teens will also now likely receive it.

KienyaddedSierra Leone's government will now need to decide if it also wants to use the ring vaccination approach.

Dr. Alison McGeer, director ofinfection control at Toronto's Mount Sinai Hospital, made multiple visits to help control the outbreak inLiberia between October 2014 and January 2015. She's excited by the early data on thevaccine.

"The amazing thing about it is the amount of progress that has been made in vaccine development in a short period of time," McGeersaid.

"We needed to do better, which is true. But still, this is the first Ebola vaccine trial.This is the first time we've ever done a vaccine trial in the middle of an outbreak. This is the first time we've ever done a vaccine trial in Guinea. There's a whole lineup of check boxes of things that are close to impossible that this this the first of. It is just an amazing accomplishment."

Dr. Andrew Simor, chief of microbiology and infectious diseases atSunnybrook Hospital in Toronto, worked in Sierra Leone in Januarytraining Ebola-fighting crews.

Simor agreed with Chan's assessment of the vaccine as a game changer.

"Had this vaccine been available a year ago, I think it had the potential to save literally thousands of lives," Simor said.

The vaccine was developed at the Public Health Agency of Canada's National Microbiology Laboratory in Winnipeg under the direction of Dr. Gary Kobinger.

Simor said the scientificwork at the Public Health Agency of Canada was critical because researchers recognized the fragment of the Ebola virus most likely to spark a protective immune response, the first step in developing a vaccine.

"We are proud of the work done by Public Health Agency of Canada scientists that led to the development of the vaccine and hope that it can be used as a global resource to help save lives and end the outbreak in West Africa," Health Minister Rona Ambrose said in an email.

The vaccine was originally licensed to NewLink Genetics and Merck & Co. has an exclusive worldwidelicensing agreement to research, develop, manufacture and distribute it.

The trial is also funded by the:

• Research Council of Norway through the Norwegian Institute of Public Health.
• The Canadian government through the Public Health Agency of Canada, Canadian Institutes of Health Research, International Development Research Centre and Department of Foreign Affairs, Trade and Development.
• WHO, with support from the Wellcome Trust, United Kingdom.