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.

Tara Hills told CBC News that since all her children, aged 10 and under, were showing symptoms of the contagious disease, they have been advised to take antibiotics and stay inside their Kanata home for five days.

Her first three children were partially vaccinated, she said. But she decided to stop after the fourth was born because she was suspicious of the medical community.

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

Three of Tara Hills's seven children peer out the window of their Kanata home in Ottawa, isolated as they get over whooping cough. (CBC) Hills said she had recently started rethinking her position on vaccinations. Before her youngest was diagnosed with whooping cough, she said, she met with her family doctor to put together a "catch-up vaccination schedule" for her children.

"It's very sobering and it's very raw because we had just made a more fully informed decision about vaccinations. We had just defected from the anti-vaccination camp," she said.

"It was too late. It's so ironic and I'm not beating myself up for it. I just hope we can use this very painful experience to encourage other people like us to maybe re-examine the issue."

Whooping cough vaccine part of routine child shots

Ottawa Public Health confirmed that there are seven reported cases of whooping cough, also called pertussis, in Ottawa, including an infant. There are about 20 cases in Ottawa per year.

"The best way to protect children against pertussis is immunization," Ottawa Public Health told CBC News in an email statement.

"The pertussis vaccine is part of the routine childhood vaccine schedule, which is given at two months, four months, six months, and 18 months old, at four to six years and again at 14 to 16 years of age."

Hills decided to share her story in a parenting blog post called "Learning the Hard Way: My Journey from #AntiVaxx to Science."

"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 wrote.

"I understand that families in our community may be mad at us for putting their kids at risk. I want them to know that we tried our best to protect our kids when we were afraid of vaccination and we are doing our best now, for everyone's sake, by getting them up to date."