Dr. Iris Gorfinkel wants parents to vaccinate their children, but she understands if they have questions first.

The Toronto physician knows that some moms and dads are skeptical of vaccinations — but not because they disregard science or question the efficacy of childhood shots. Instead they worry that their kid could be the one-in-a-million patient that has a serious, adverse reaction.

"Probably about 10 years [ago], I started saying: 'Well, we've got to open up a better dialogue in trying to understand where that person is coming from,'" she told Day 6 host Brent Bambury.

Vancouver Coastal Health reported Wednesday that the health authority is treating 15 cases of measles in B.C.

The cases traces back to three children who contracted the virus during a family trip to Vietnam. Their father told CBC News they rejected the measles, mumps and rubella (MMR) vaccine due to fears it could cause autism.

Meanwhile, the World Health Organization calls "vaccine hesitancy" a major global health threat.

We see serious adverse events in three out of one million vaccinations. - Dr. Iris Gorfinkel , Toronto physician

Parent Tracy Hilliard rejects the narrative that vaccines cause autism, but she had reservations when she took her two-month-old to the family doctor for his first vaccines.

She was scared to express those concerns.

"I really, really convinced myself that … you're going to be the one who ends up with a dead child today," Hilliard told Day 6.

But, Hilliard recalls, her doctor took the concerns seriously and said she would be nearby if anything went wrong.

Don't show them the door

According to Dr. Gorfinkel, data suggests that up to 30 per cent of parents may have some hesitancy when it comes to vaccinating their children.

In the earlier days of her practice, Gorfinkel says she would have shown parents who reject medical science "the door."

Tracy Hilliard, though not anti-vaccine, worried about whether her son would be the one-in-a-million patient to have an adverse reaction. Dr. Iris Gorfinkel says these worries are natural and understandable. (Eddie Keogh/Reuters)

Now, she's more measured, asking parents what worries them: pain? Inflammation? The post-shot fever? That's something she says is needed in medicine today.

Arguing with parents may lead them to "literally walk away from what I'm saying," Gorfinkel said.

"Ultimately without that emotional connection a lot of medicine doesn't work," she added.

But some parents present more serious worries, like the possibility of an extremely rare, adverse reaction. Gorfinkel attempts to calm those worries with statistics.

"We see serious adverse events in three out of one million vaccinations," she said.

"For me as a family doctor that translates into, in a career of 27 full-time years of general practice, I have never seen a serious adverse event with a vaccination."

'Get their head out of the internet'

Tracy Hilliard's concerns began when she browsed "mommy blogs" for advice from other mothers on breastfeeding.

Some of those mothers, she said, were "anti-vaxxers" who would start online fights about who was right and wrong.

Her son, now 4, is vaccinated — without any serious side effects — but groups continue to stoke fears by highlighting those rare, but possible, adverse reactions.

A not-for-profit group, Vaccine Choice Canada, purchased 50 digital billboards throughout Toronto. On Wednesday, they displayed messages suggesting that vaccines were unsafe for children.

Vancouver Coastal Health has reported 15 measles cases in an outbreak stemming from three children in a French-language school in Vancouver. (Sean Holden/CBC)

The billboards were purchased with fundraised money, but removed by Outfront Media, the owner of the billboard properties, later that day.

"I am trying to imagine the psyche of the person who actually erected the billboards," Gorfinkel said.

"You're talking about this tiny, tiny population who happens to have a few dimes on their pocket and instead of spending it on something that is valuable to the community they actually destroy the community."

Still, if a parent who rejects vaccines walked into her office, she wouldn't turn them away. Gorfinkel says she would suggest a slowed roll-out.

If a child requires multiple vaccines, she might suggest administering them once per visit instead of several at a time, she told Day 6.

Hilliard's response is more straight-forward.

"I'd tell them to talk to their doctor and, if they could, get their head out of the internet," she said.

To hear the full interview with Dr. Iris Gorfinkel, download our podcast or click 'listen' at the top of this page.