Major survey to monitor safety of COVID-19 vaccines in Canada

February 25, 2021

By Jennifer Stranges

Headshot of Dr. Matthew Muller

Dr. Matthew Muller

A sweeping national survey is tracking whether and how often adverse events occur after COVID-19 vaccination, offering critical insight as immunization campaigns intensify and new vaccines are approved for use in Canada.

The study, led by the Canadian National Vaccine Safety (CANVAS) Network, a national platform that monitors vaccine safety, aims to enrol 300,000 participants for each Health Canada-approved vaccine. The participants will be residents of B.C., Yukon, Alberta, Ontario, Quebec, Nova Scotia and P.E.I. St. Michael’s Hospital, part of the  Unity Health Toronto network, is the lead site for CANVAS in Ontario.

The study comes as Canada’s mass-vaccination campaign ramps up after supply chain delays and provinces and territories expand their immunization efforts.

“These are new vaccines and it is critically important to monitor what happens when millions of Canadians are vaccinated over a prolonged period of time,” said Dr. Matthew Muller, Medical Director of Infection Prevention and Control at St. Michael’s Hospital, and Ontario lead for the CANVAS Covid-19 vaccine project.

“This will help use be absolutely sure that there are not any unanticipated side effects from these vaccines. Ongoing monitoring for side effects in large numbers of vaccinated Canadians is critical to reassuring the public that these vaccines are safe and to encourage everyone to be vaccinated.”

Study participants will be asked to complete online surveys eight days after they receive the first COVID-19 vaccine, another eight days after the second dose – if they receive one – and then a final survey six months after that. The surveys will collect basic demographics data and information about illnesses since the participant’s most recent dose.

Researchers will also enrol a control group of approximately 50,000 unvaccinated participants to complete surveys. These non-vaccinated participants will help the researchers understand how common certain symptoms are in the general population.  For example, if five per cent of unvaccinated participants had moderately severe headaches in the previous week and three per cent of people have a moderately severe headache within a week of being vaccinated, this would provide reassuring data that these headaches are not due to vaccination.

The CANVAS Network, launched over 10 years ago, conducts active safety surveillance for pandemic vaccines, such as the H1N1 influenza vaccine in 2009, seasonal influenza vaccines and other new vaccines to inform public health authorities about their safety.

“Tracking vaccine safety is a critically important task which CANVAS conducts for many vaccines,” says BC Children’s Hospital investigator Dr. Julie Bettinger, lead investigator for the CANVAS network. “We are massively scaling up this work to find out whether and how often any adverse reactions occur after a COVID-19 vaccination.”

The Canadian Institutes of Health Research and the Public Agency of Canada provided funding for the COVID-19 vaccines safety web survey project, which, as well as the five CANVAS sites, includes public health collaborators from four provinces and territories and the Canadian Immunization Research Network, a research network, of which CANVAS is a part.

Canadians interested in enrolling in the study can visit to learn more.

“We believe CANVAS will continue to show that the currently approved vaccines are safe, but it is critically important that we make no assumptions and get the best possible data to confirm that each and every vaccine offered to Canadians is safe – and you can help us,” Dr. Muller said.