Lifelong flu vaccine moves closer with Canadian research

Getting your flu shot every year can be a pain in the arm and many people skip the annual needle.

But scientists say they're getting close to a universal flu vaccine that would offer lifelong protection.

Teams of scientists in the U.K., U.S, Australia and Canada are working toward that goal.

The advantage of a one-shot vaccine is that it would increase the number of people who could be vaccinated and decrease the risks of a flu pandemic, like the 1918 strain that killed as many as 50 million people worldwide.

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Right now, Canadians can go to their doctor or pharmacist and get a seasonal flu vaccine that is designed to fight that season's variant of influenza.

Flu changes every year

"The issue with those vaccines is that we have to get them every year because the flu changes every year," says Matthew Miller, an assistant professor in the department of biochemistry and biomedical sciences at McMaster University in Hamilton.

"The difference between those vaccines and the universal vaccine is that the universal vaccine works in way whereby it will still be effective even when the virus mutates."

Miller is working with scientists at the Icahn School of Medicine at Mount Sinai, New York, and the University of Chicago to develop a universal vaccine.

Their research, published in the journal Proceedings of the National Academy of Science USA (PNAS), centres on a group of antibodies in the human body that can be triggered to fight all strains of flu.

These antibodies "stick to the surface of infected cells and call in other cells of your immune system to kill the virus," he told CBC News. Thismimics a process that occurs naturally, triggering white cells to surround a virus and kill it.

At the cellular level, the trick has been to target the stalk of the virus, which is similar in most flu strains, rather than the head, he explained.

Next step is clinical trials

While the team is still working on the science of how the vaccine works, Miller said his team has already developed an effective vaccine.

The next stage is clinical trials, which will necessitate support from pharmaceutical companies and government regulators. He estimates such a universal flu vaccine could be on the market in five to 10 years.

Of all the diseases that are currently out there, flu is the only one that over the course of the last 100 years has constantly demonstrated its ability to cause pandemics in humans.- Matthew Miller, McMaster University researcher

"It targets an area of the virus that is the same among all types of flus basically, even ones that we've thought could never infect humans before so it's not susceptible to the virus changing," Miller said.

With seasonal vaccines, there is sometimes a mismatch, as in 2014-15 when that year's vaccine targeted the wrong strain of flu. That problem is avoided with a universal shot.

Flu is a killer

Miller said people should take flu more seriously than they do.

"Of all the diseases that are currently out there, flu is the only one that over the course of the last 100 years has constantly demonstrated its ability to cause pandemics in humans. Since 1918, we've had four flu pandemics and we've had essentially no other pandemics of infectious agents, other than HIV," he said.

While young, healthy people's immune systems usually respond quickly to each new strain of flu, the elderly and young children are much more vulnerable.

Protection against flu pandemics would be a huge step forward for public health, Miller said.