As Vancouver Coastal Health reaches out to all Vancouver students amid a measles outbreak in the city, anti-vaccination parents are spreading misinformation and a new petition fighting immunization efforts.

Health officials have confirmed nine cases of measles, all but one of the students at three Vancouver French-language schools.

While the letter VCH sent to the school district stresses "there is no evidence of measles transmission into the wider community" it also encourages those born after Jan. 1st, 1970 and "unsure of your immunization history and unable to locate your records, we recommend that you get a dose of MMR vaccine."

A small but vocal number of parents are pushing back against health officials and media coverage encouraging those without measles vaccines to get inoculated.

A commenter on a CTV News story about the outbreak wrote she is a "second generation no vaxx person...I never had an issue. And now I'm doing the same with my four children."

In response to a petition by Maple Ridge mother Katie Clunn aimed at making immunization mandatory at public schools, a counter-petition has emerged from the anti-vaxx community titled "Maintain the right to choose what happens to your children."

It calls Clunn's petition "horrible and disgusting" with one supporter writing she wants to "get vaccination clinics out of schools and get uninformed do-gooders out of people's private health decisions."

"We think there's probably around two to three per cent who absolutely refuse all vaccines, they don't want to vaccinate and there's nothing you can say that will convince them," UBC pediatric professor Julie Bettinger told CTV News.

Bettinger researches vaccines, their efficacy and side effects, as well as public response to vaccine messaging for the Vaccine Evaluation Centre at BC Children's hospital.

"There's probably another 15 to 20 per cent who are 'hesitant,' meaning they may have gotten all the vaccines but still have questions about it -- or they may actually have skipped some of the vaccines or may not be vaccinated at all."

Bettinger says the idea of injecting virus cells to develop immunity to life-threatening illnesses has had skeptics and people refusing to participate since vaccines began to be widely used in the early 1800s.

But the now-discredited study of Dr. Andrew Wakefield published in 1998 fuelled existing concerns. It falsely claimed a link between autism and the measles vaccine and wasn't thoroughly debunked and retracted until 2010 – long after it had provided fodder for websites on the then-fledgling internet to spread the idea far and wide.

"It actually makes me mad because this is someone who was a fraudulent researcher, who has harmed how many hundreds of thousands of children based on evidence that he made up," says Bettinger.

Measles had been all but eradicated in North America, but vaccine hesitancy has decreased the effect of herd immunity in some communities, allowing the virus to take hold when travellers become infected in parts of the world where the disease is still relatively common.

In 2014, BC saw 232 cases of measles, mostly in the eastern Fraser Valley, while a 2010 outbreak saw 87 cases. Measles can be fatal, especially in children.

Nonetheless, anti-vaxx parents question the efficacy and need for "forced" inoculation, with some claiming vaccines are more dangerous than the illnesses they're designed to prevent or that they can even spread diseases.

Immunize BC refutes such misinformation through a series of explanatory articles describing rare potential side effects and why it's important to vaccinate.

It's worth noting that last year, researchers at George Washington University analyzed social media postings from Russian trolls and bots that they determined were geared at disseminating anti-vaccine messages.

"Accounts masquerading as legitimate users create false equivalency, eroding public consensus on vaccination," concluded the researchers.

While Vancouver doctors tell CTV News there's anecdotal evidence of a surge of B.C. teens and young adults raised in anti-vaxx homes seeking out immunization - which is free and available to everyone who asks for it - since the outbreak, there is still a stubborn segment of the population that is susceptible to fear tactics and persistent misinformation campaigns.

"It's amazing to me when I do my research and find anywhere from 10 to 30 percent of parents who I'm surveying or speaking to who think that the measles vaccine is linked to autism," says Bettinger.

"They still think that in spite of the mountain of scientific evidence showing that's not true."