A new Angus Reid poll suggests the number of parents opposed to vaccinating their children has grown over the last five yearsin Canada.

One in six parents of children under 18said they are “really against” getting their kids vaccinated, the poll published Wednesday said.

That's 17 per cent of the parents polled earlier in February, compared to four per cent of parents who held that view in 2019.

In addition, the proportion of parents who said they would vaccinate their children “without reservation” decreased from 88 per cent in 2019 to 67 per cent.

“What we see in the data is there's been a notable shrinking of that level of enthusiasm among parents to vaccinate their children,” said Shachi Kurl, president of the Angus Reid Institute, in an interview.

The poll also found that fewer people support mandatory childhood vaccinations now than five years ago. In 2019, 70 per cent of Canadians polled agreed that vaccinations should be mandatory for a child to attend daycare or school. That percentage dropped to 55in 2024.

Support for mandatory childhood vaccinations was highest in Ontario at 61 per cent, where routine vaccinations for diseases including measles, mumps, rubella, tetanus, whooping cough and polio are required to attend school. People in Quebec and Alberta were the least supportive of mandatory childhood vaccinations, at 45 and 48 per cent, respectively.

The survey comes amid a global rise in measles - a disease that is preventable through routine childhood vaccinations. Public health agencies in Canada are on alert because travel-related cases are appearing in Canada, and getting children vaccinated is essential to ensuring measles doesn't spread locally.

Many people in Canada are concerned about that, the poll suggests, as seven in 10 respondents said they are worried about rising anti-vaccine sentiment causing unnecessary illnesses.

In addition, the percentage of Canadians who say opposing childhood vaccination is irresponsible has remained fairly steady at above 70 per cent over the past five years, the poll says.

“Immunization is one of the most important preventive health measures we have - responsible for saving millions of lives,” the Canadian Paediatric Society said in an emailed statement responding to the poll results.

“We know parents want to do what's best for their children, but misinformation about vaccines has caused a lot of confusion and distrust,” the society said.

“As health-care providers, we have to be ready to hear and understand where their hesitation is coming from, and be prepared to answer questions about the illnesses vaccines protect against, how effective they are, and how safe they are.”

Although the poll did not specifically ask whether the push for COVID-19 vaccinations affected people's attitudes toward childhood vaccination overall, Kurl said there is likely a connection.

“(With) the passage of time and the hesitancy around COVID-19 vaccination, it's impossible to not correlate that to some extent with this decline in vaccination enthusiasm and this increase in, at best, vaccine skepticism or frankly even anti-vaxx sentiment,” she said.

However, Kurl noted that even before the pandemic, Angus Reid was already seeing “lower levels of vaccine approval or vaccine acceptance, even going back to 2015, among younger age demographics.”

Older Canadians have the highest level of vaccine acceptance, she said.

“If you're somebody who's 60-plus, maybe a parent or grandparent lived with polio or some of those other childhood diseases, so there's a better understanding and I think perhaps less likelihood to reject the benefits of vaccination, particularly childhood vaccination,” Kurl said.

The poll results come from an online survey of 1,626 Canadian adults who are members of the Angus Reid Forum, conducted between Feb. 16 - 19.

Online surveys cannot be assigned a margin of error because they do not randomly sample the population. Angus Reid says for comparison purposes, a probability sample of this size would carry a margin of error of plus or minus two percentage points, 19 times out of 20.

This report by The Canadian Press was first published Feb. 28, 2024.