TORONTO -- Many Canadian chiropractors who advocated against vaccinations have removed vaccine-related information from their websites after attracting extensive coverage by media outlets, according to a new study.

The study from McMaster University in Hamilton, Ont. has found that half of chiropractors who provided mostly negative vaccine information on their websites have removed those posts in the last three years.

Chiropractor and McMaster associate professor Jason Busse said in a press release that the removal of vaccine information from chiropractors' websites was associated with an increase in Canadian media coverage on the topic.

"The Canadian media has drawn attention to anti-vaccination statements by some chiropractors, and that seemingly had a large impact on curbing publication of such online material," Busse said. "While this is laudable, chiropractic regulatory colleges should monitor chiropractors' websites and social media accounts for misleading information and enforce their standards of practice."

According to the press release, chiropractic is Canada’s third-largest regulated health-care profession with approximately 9,000 practitioners across the country.

The study, published Tuesday in the Canadian Medical Association Journal (CMAJ) Open, focused on Canadian chiropractors' websites over a three-year period.

Researchers said they identified 94 out of 3,733 chiropractic websites in July 2016 that provided information on vaccinations. According to the study, almost 63 per cent of these websites were critical of vaccination, 20 per cent were neutral and 17 per cent were supportive.

The study reported that the vaccination content was generally poor with a median score of 19 per cent from online health information assessment tool Web Resource Rating. According to the study, posts on chiropractic websites included offering alternatives to vaccination, claims that vaccination is harmful, mixed evidence regarding vaccination and concerns regarding vaccination policy.

When looking at media coverage, the study found only one Canadian newspaper story concerning anti-vaccination statements by chiropractors between 2012 and 2016. However, between 2017 and 2019 researchers found 51 news articles published on the topic.

Three years after a number of Canadian media outlets began reporting on anti-vaccination statements made by chiropractors, researchers found that approximately half (47 per cent) of the websites identified in 2016 had been discontinued or removed all content regarding vaccinations.

"Historically, some prominent chiropractors have been extremely critical of vaccination, and a number of traditional practitioners maintain these attitudes," Busse said.

This includes Halifax-based chiropractor Dena Churchill who surrendered her professional license last year and was ordered to pay $100,000 after admitting professional misconduct for spreading vaccine skepticism on her blog "Dr. Sexy Mom."

"It may be helpful for medical and public health associations to work with Canadian chiropractic associations to collaborate on promotion of vaccination programs," Busse said.

The College of Chiropractors of Ontario standard was amended in 2018 and 2019 to prohibit chiropractors from providing vaccine information on their websites and social media accounts.

The Canadian Chiropractic Association also updated their position statement in late 2019 explicitly stating that "vaccination is a safe and effective public health practice for the prevention of infectious diseases."