An experimental Canadian-made vaccine is one of the leading contenders in the unprecedented race to develop a tool that will stop the deadly Ebola epidemic.

As a massive Ebola outbreak continues to take lives in West Africa, the largest Ebola vaccine trial on humans is about to get underway in Switzerland.

The researchers will begin testing new drugs on 120 volunteers in the town of Lausanne.

Researchers are trying to determine two things: the safety of the vaccines and the correct dosage.

Scientists in the United States recently completed the first tests of the Canadian-made VSV-EBOV vaccine on 13 people to gauge its safety.

Dr. Shon Remich, a vaccine researcher at the Walter Reed Army Institute of Research, said they also expect to have some idea of immune response in the next three to four weeks.

“All the data we have from the initial low-dose group is being reviewed by a scientific review committee and they will give us permission whether we can move into an intermediate dose and high dose,” Remich said.

The next phase includes testing with higher doses in more people. The tests will take place in Switzerland and the African countries of Gabon and Kenya.

A second experimental vaccine, produced by GlaxoSmithKline, is already being tested on health care workers in Mali.

The GSK product uses a harmless cold virus to deliver inactive components of the Ebola virus (Zaire Strain) into the immune system.

“It sort of tricks your body into thinking there might be Ebola around, but you don’t get sick from it, you don’t get Ebola,” said Dr. James Campbell, a researcher at the University of Maryland’s School of Medicine.

Ensuring vaccines are safe is the easy part of this testing. Questions remain over whether the vaccines will work, and what is the correct dose. Also, if a vaccine is deployed, officials will need to find a way to keep thousands of doses refrigerated in Africa’s intense heat.

Another hurdle is determining whether the vaccine has protected people from infection if they are also using personal protective equipment in health care settings. Is it the precautions or the vaccine that safeguards the person?

It’s also not clear whether trial data will come quickly enough to allow vaccines to be used in the current outbreak in West Africa.

“That’s the only reason why we’re working nearly 24-7, trying to make this happen so quickly,” Campbell said.

But some researchers say they’re ahead of schedule and are hoping to start larger clinical trials in December.

Remich, meanwhile, says Canada should take pride in what could be a large contribution to the fight against Ebola.

“If you take Canada out of the equation, we don’t have a vaccine, so I think there’s a lot that Canadians have to be proud of,” Remich told CTV News.

With files from CTV Medical Specialist Avis Favaro and producer Elizabeth St. Philip