The vast majority of Canadians believe vaccines are effective, and about three-quarters of the country agrees people who oppose childhood vaccines are "irresponsible," a new poll suggests.

The Angus Reid poll of more than 1,500 Canadians, released Friday, comes as cases of measles spike in some parts of the United States and Canada.

Doubts over vaccines have gained enough traction that Health Minister Rona Ambrose spoke out in favour of vaccines recently, warning that children were being put at risk by the anti-vaccination movement.

The online poll, conducted from Feb. 9 to 11, found broad support for vaccinations:

  • Eighty-eight per cent of respondents said vaccinations prevent diseases in individuals, while slightly less (86 per cent) said they were effective for the community as a whole.
  • Eighty-three per cent said they would vaccinate their own children.
  • Seventy-four per cent agreed people who oppose childhood vaccinations are "irresponsible."
  • Almost two thirds of respondents (63 per cent) said vaccinations should be mandatory.

Despite the strong numbers in favour of vaccines, the poll suggests there are still doubts: Almost two in five respondents (39 per cent) said they agree that "the science on vaccinations isn't quite clear."

About three in ten respondents believed "serious" side-effects may accompany vaccinations.

Shachi Kurl, senior vice president at Angus Reid, said perhaps there are some gaps in communicating the efficacy and science of vaccines. 

"At the same time, it doesn't seem to be affecting the overall Canadian view of whether or not vaccines work," Kurl said. "Perhaps Canadians don't feel that they need to know that the science is clear in order to understand that they work."

Since measles is so highly infectious, doctors say a 95 per cent vaccination rate is needed for "herd immunity" in the population to prevent outbreaks

Both adults and children need to be educated to appreciate the high-quality science behind why vaccination works and recognize pseudoscience, said Dr. Noni MacDonald, a professor of pediatrics at Dalhousie University in Halifax, who also works in pediatric infectious diseases at the city's IWK Health Centre.

"We need to inoculate against the anti-vaccination websites," MacDonald said. 

Health-care professionals need to find out out what questions parents have and answer them, she said. 

Regional variations

There were also regional variations, with Quebec showing the lowest belief in vaccines (75 per cent) and the most widespread agreement with a risk of serious side-effects (35 per cent.)

"Quebecers, compared to the rest of Canada, are a little bit more equivocal, are more divided on some key issues, but overall, the majority in Quebec still say vaccines are effective," Kurl said. 

Quebec Premier Philippe Couillard, a physician, pointed to the success of vaccinations in preventing polio.

"The truth is vaccination is a huge progress in our society," Couillard told reporters in Montreal on Friday. "I recognize that courts have told us that you cannot make it compulsory, but on the other hand, I don't find it responsible for a parent not to follow the recommended immunization schedule."

At the time of the survey, measles was not top of mind in Quebec, MacDonald noted. She also said vaccination resources in French are not as common or easily accessible as those in English. 

People aged 18 to 34 and people with a high school education or less were also slightly less inclined to say vaccines are effective.

Most people believe in the science of vaccination, Catherine Maule, a mother, said during a P.A. Day at the Ontario Science Centre in Toronto.

"I think it comes down to ideology," Maule said. "We certainly have enough evidence, and if that's not convincing, then we need to be having a different conversation."

Respondents more prone to agreeing vaccines are effective included Atlantic Canadians, people over age 55, and people with university degrees.

The survey was self-commissioned by the Angus Reid Institute and involved 1,509 Canadian adults. 

With files from CBC's Thomas Daigle