An Ottawa mother of seven "defected" from the anti-vaccination movement, but then her youngest — a 10-month-old son — contracted whooping cough before she could get all of her children their shots.

A Canadian mother-of-seven has been forced to rethink her anti-vaccination stance – after all her children fell sick with whooping cough.

North America has seen a growing number of families opt out of immunisation programmes, frequently because they are concerned about side-effects, despite warnings that deadly childhood diseases such as measles are on the rise.

Tara Hills and her husband decided to stop vaccinating their children six years ago after losing faith in the health care system, according to a blog post in which she described the family's experience.

"I'm writing this from quarantine, the irony of which isn't lost on me," she said.

Although her first three children were immunised - on what she described as an "alternative schedule" - the youngest four received no vaccinations at all.

"I just got scared. I got spooked. I thought, 'There's a lot of smoke, there must be fire.' We stopped vaccinating," she told CBC News.

Then last month the coughing began. It sounded like a bad cold at first.

"But a week after the symptoms started the kids weren't improving, in fact they were getting worse," wrote Hills. "And the cough. No one had a runny nose or sneezing but they all had the same unproductive cough."

A trip to the doctor's surgery was followed by hospital tests, which confirmed whooping cough.

The highly infectious disease takes its name from the characteristic whoop noise that young children make following a cough as they struggle to catch their breath.

Young infants are at particular risk of severe complications and even death.

Vaccinations have massively reduced the number fatalities, which once ran at 10,000 a year in the US, according to KidsHealth.

Yet cases are on the rise again as parents – frequently well educated and middle class – shun the scientific evidence.

Hills admitted she had recently begun to rethink her stance, as the number of measles outbreaks began to grow.

Now with her six sons and a daughter, aged from 10 years to 10 months in quarantine at their home in Ottawa, she said she was doing her best to get them all up to date with their vaccinations. She added that any parents with doubts should be able to find good, reliable data about the benefits.

"I am not looking forward to any gloating or shame as this 'defection' from the antivaxx camp goes public, but this isn't a popularity contest. Right now my family is living the consequences of misinformation and fear," she said.

Get more Stuff stories on our Facebook page.