The World Health Organization says researchers are working as quickly as they can to make two experimental Ebola vaccines available to those who need them most, in hopes of stemming an outbreak that shows no signs of slowing. But they admit they are trying to accomplish in a matter of months a process that normally takes years.

There are high hopes that two experimental vaccines, including one developed in Canada, will quash the outbreak in West Africa, which has become "the most severe acute public health emergency seen in modern times” according to WHO.

Both vaccines have been in testing for over a year and have performed well in non-human primates. They appear to not only prevent infection, but also to halt an infection if given early enough.

Researchers are now hoping Phase 1 studies will find the vaccines safe for use in humans. In the U.S., researchers have already begun to enrol volunteers to test one vaccine, called cAd3-ZEBOV, which has been developed by GlaxoSmithKline in collaboration with the U.S. National Institute of Allergy and Infectious Diseases.

The other vaccine, rVSV-ZEBOV, was developed by the Public Health Agency of Canada in Winnipeg, with a small U.S.-based company holding the license for commercialization. (That company is BioProtection Systems, a subsidiary of NewLink Genetics.) The first Phase 1 trial of that vaccine is due to start early this month.

But while human testing has begun, Phase 1 studies assess only a vaccine’s safety, not how well it works. That will require a second phase of study with new volunteers -- a process that could take months more.

WHO acknowledged Wednesday that vaccine development is often lengthy and costly.

“Even under the best conditions and with the massive efforts of many partners, a significant number of doses will not be available until late in the first quarter of 2015,” they stated.

In the meantime, WHO says it may allow health-care workers working on the frontlines of the epidemic to receive the Ebola vaccines even before their effectiveness has been fully studied.

“Vaccine doses could be deployed to consenting frontline health workers before all testing has been completed,” the agency said. “The decision to initiate such deployment should be informed by data emerging from the Phase 1 studies, and will occur with data collection on the deployment itself.”

It’s an unusual step for WHO and for vaccine developers. But these are unusual times -- with the epidemic still out of control, the risks of infection high for health-care workers, and a lack of effective treatment.

Canada has already promised to donate 800 to 1,000 doses of its stockpile of rVSV-ZEBOV to WHO but those vials remain in Canada.

Canada’s new chief public health officer, Dr. Gregory Taylor, told reporters Wednesday the doses are ready to be shipped at a moment’s notice, but they are waiting for the go-ahead from WHO.

“We’re trying to move this as quickly as possible from a humanitarian basis,” he said, adding, “The WHO has never done this before -- the world has never done this before with experimental vaccines.”

Taylor says because the vaccine has never been used on humans, all parties want to be assured the vaccine is both safe and that its use will be part of a scientific study to ensure that data on its safety is recorded.

“If one of these vaccines injured someone, it would set everything back,” he said.