The largest Ebola outbreak in history is defying the containment efforts of affected countries and international response teams, leading to calls from some quarters to use experimental drugs or vaccines to try to stop the deadly virus.

But a number of experts — including the scientist who led the work on a Canadian-made Ebola vaccine — say deploying untested tools in the current West African outbreak could be disastrous.

They say taking such a risky gamble could further erode local trust in the response teams, undermine their efforts and even endanger them. And if anyone were to have a bad reaction to one of the experimental therapies, it could jeopardize years of expensive and painstaking work spent developing tools with which to fight Ebola and its cousin, the Marburg virus.

Read more on thestar.com:

Secret weapons for stopping Ebola? Humanity, trust and respect

Ebola outbreak ‘very challenging,’ says WHO

Ebola outbreak in West Africa ‘out of control,’ says MSF

“I get emails basically every second day from someone either asking, ‘Is there something that you’re planning?’ or ‘Shouldn’t you?’ And I know I’m not the only one getting those emails,” says Dr. Heinz Feldmann, an Ebola expert with the U.S. National Institute of Allergy and Infectious Diseases.

While most of these discussions are happening within scientific circles, the director of Britain’s Wellcome Trust recently aired the issue publicly.

Dr. Jeremy Farrar, an infectious diseases expert, has questioned why the therapies that are furthest along in the developmental pipeline aren’t being used. He suggests if this outbreak were occurring in the developed world, there would be no debate.

“Imagine if you take a region of Canada, America, Europe and you had 450 people dying of a viral hemorrhagic fever. It would just be unacceptable — and it’s unacceptable in West Africa,” Farrar says.

He notes the Canadian-made Ebola vaccine — a project Feldmann led a decade ago when he worked at the National Microbiology Laboratory in Winnipeg — was released under emergency-use provisions in 2009 when a German researcher pricked herself with a needle containing Ebola virus. She survived, but it was never clear if it was because of the vaccine or because she was not infected.

A small community of researchers, mostly based in Canada and the United States, has been working for years on vaccines and drugs to protect against or treat these viruses, which are among the deadliest known to humankind. The viruses are transmitted through contact with bodily fluids. People caring for the dying — or preparing their bodies for burial — are often infected.

With little to offer medically, the main job of response teams is to break the chains of transmission by figuring out who is infected and isolating them. But these efforts are often met with distrust. Rumours emerge that the Western doctors are harvesting organs; people hide cases or flee — extending the range of the epidemic.

Loading... Loading... Loading... Loading... Loading... Loading...

The World Health Organization says the current outbreak — the first in West Africa — has seen 844 cases in three countries, and 518 deaths. That’s already virtually double the size of the next largest outbreak, in Uganda in 2000. And this outbreak isn’t anywhere near over.

A number of vaccines are in various stages of development. Studies done in non-human primates suggest they could both prevent illness and improve survival chances if given after infection. There are also a number of therapies in the works, including antibody combinations that look promising in animal testing.

But the researchers have always been stymied by the challenges of getting regulatory approval for these interventions, which cannot follow the traditional pathways to licensure. Most drugs or vaccines can only make it to market once large-scale studies show they are both safe and effective. But the only way the world will learn if Ebola and Marburg vaccines and drugs work is by using them in an outbreak — a reality rife with ethical concerns and logistical problems.