Canadians signing up to be deliberately infected with flu virus to aid vaccine research

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Canada first needed special isolation units, the challenge viruses and the expertise. “And then you have to convince everyone around you this is OK to do,” Ward said. “Each of those steps took a lot of time.”

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The new project, in collaboration with the Canadian Center for Vaccinology at Dalhousie, began in June with the first eight volunteers in Halifax; two more participants have now started the study in Montreal. The research will eventually involve 32 people, 16 at each site, all healthy adults ages 18 to 45 who have no known risk factors for severe influenza, a disease that contributes to an estimated 3,500 deaths in Canada each year.

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Researchers are using an attenuated, or weakened H3N2 virus that’s diluted in glucose and saline and sprayed into the nose as an aerosol. Volunteers are being intensively studied “from the moment that we infect them,” Ward said. H3N2 is a subtype of influenza A. Influenza A viruses are on the short list of viruses that can cause global pandemics, Ward said.

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Half the volunteers are getting a low dose; the other half, a higher one. One out of every group of four is getting a saline placebo. At the higher dose, it’s expected 60 to 70 per cent will end up with mild to moderate symptoms.

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All remain isolated for a minimum seven days in specially designed negative-pressure rooms that keep potentially contaminated air or other particles inside the room from circulating outside the room.

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People are monitored 24/7 by one or two nurses and undergo regular blood tests and nasal swabs. Ward is on call 24-hours a day. “If these people show any signs of getting into trouble, we will be on top of it immediately and start antivirals,” he said.

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The experiments will help better understand how the human body responds, even within the first few hours, to influenza, a “slippery family of viruses” that, unlike measles, “mutate like crazy,” Ward said.

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“One of the big problems with understanding how our human body responds to any pathogen is that it’s awfully difficult to know when somebody got infected,” Ward said.

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Some volunteers exposed to flu won’t show any symptoms at all. “What did their bodies do right that shut down that possible infection before it started,” Ward said. “We may find early biomarkers of a successful response.”

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The team isn’t testing a vaccine this round but hope to create a model for future vaccine challenge trials, Ward said. “How do you recruit people to do this kind of study? How do you convince your research ethics board this is an OK thing to do?”

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In the event of a deadly influenza pandemic, for example, “two, three, 10, 20 different vaccines” could be tested in a challenge trial to determine which offer the most by way of individual protection and reducing community transmission, Ward said.

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In the influenza infection study, “You have to have a very frank conversations with the volunteers,” Ward said. “Because every now and then — extremely rarely, but every now and then — a healthy individual gets flu and ends up in the intensive care unit, because their body happens to react over-strenuously to that particular viral challenge.”

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Ten per cent of the adult world gets infected every year with influenza. “It’s not like we’re doing something that is unlikely to ever happen to you otherwise,” Ward said, but added that “we do everything we can do to mitigate” risks.

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While Ward said he’s excited the trials are happening, “I wouldn’t be honest if I didn’t say I was also really nervous.

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“It is a little bit on the edge to be working with these volunteers and trying to do good science and make sure we aren’t doing any harm.”

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Volunteers are being remunerated commensurate for giving up seven to 10 days of their lives, Ward said, though he declined to give exact amounts.

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The work is being funded through a pandemic-preparedness grant from the Canadian Institutes of Health Research.

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National Post

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