If you're undecided about getting a flu vaccine, new Canadian research on how inflammation after getting the flu and other respiratory illnesses might contribute to dementia and cardiovascular disease could help you make up your mind.

A research team at McMaster University in Hamilton suggests that getting vaccinated regularly now can protect us from other diseases later.

Prof. Dawn Bowdish, who holds a Canada Research Chair on Aging and Immunity, has been digging into the reasons older people are more prone to other illnesses after getting the flu.

She concludes the inflammation linked to the flu and other respiratory illnesses doesn't really go away, and contributes to things like dementia, cardiovascular disease and Type 2 diabetes.  

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"It's a terrible cycle where once you start getting these respiratory infections, they often precipitate and make you more susceptible to more infections and more of this chronic inflammatory disease."

Bowdish's research is focused on mice because they most closely model the human immune system. Lab tests show when elderly mice received flu vaccines early in life, they were healthier and less likely to get other chronic illnesses as seniors.

Flu lab mouse

The flu study undertaken by McMaster University researchers focused on mice because they most closely model our immune system. (CBC)

But old mice that were never immunized not only got other diseases sooner, but when they were hit with the flu, it accelerated the progress of those diseases in the long term.

Bowdish believes flu vaccinations should start early because it works well in kids and reduces the risk of spreading the flu to older people.

"Every year we invest in a vaccination is a year we invest in good health late in life," she says.

Still, convincing people to get the flu shot can be a tough sell. Bowdish can't even persuade her own mother to get vaccinated. Bowdish did, however, convince her husband to start getting the jab.

Overall, two-thirds of Canadians still don't get immunized.

Almost all provinces and territories are in the midst of their annual flu vaccination campaigns. So far, one eastern region in Ontario and two regions in British Columbia have shown localized flu activity, according to the Public Health Agency of Canada.

The researchers are now using what they've learned about flu shots to try to block inflammations in older mice. They're also zeroing in on a way to boost protective microbes in the nose and lungs.