With more than a million participants enrolled in its study, the Canadian National Vaccine Safety Network (CANVAS-COVID) shows that more than 90% of those who are vaccinated do not experience any side effects other than temporary and localized pain at the injection site. Dr. Julie Bettinger, from the British Columbia Children’s Hospital Research Institute and University of BC, presented some of the latest results from the CANVAS-COVID vaccine safety survey at the Canadian Immunization Conference on December 8, 2021.

Key findings:

  • Temporary and localized injection site reactions are frequently reported after getting a COVID-19 vaccine, no matter the manufacturer. The breakdown of participants experiencing localized injection site reactions following each dose are as follows:
    • Comirnaty (Pfizer-BioNTech): 49% after dose one, 62% after dose two.
    • Spikevax (Moderna): 62% after dose one, 65% after dose two.
    • Vaxzevria (Oxford-AstraZeneca): 44% after dose one, 45% after dose two.
  • Most participants (91%) do not experience any other health event following vaccination.
  • Of the health events reported that prevent work, school, and/or daily activity, and/or require medical care, the most common were systemic symptoms such as joint pain, fever, headache, muscle aches.
  • Adverse effects following vaccination with Comirnaty occur at the same rate as those in the unvaccinated comparator group.

CANVAS-COVID is an <span class=”definition”>active surveillance program<span class=”definitiontext”>Active vaccine safety surveillance entails the proactive investigation of adverse events following immunization through meticulous scanning of health records and surveying of vaccinated individuals to look for health events that may be linked to vaccines.</span></span> relying on self-reported adverse events following immunization, including those that prevent daily activities and/or require medical attention. This information is collected via web-based surveys sent out to vaccinees eight days following receipt of a first dose and second dose of a COVID-19 vaccine, with a follow-up seven months after the first vaccination. The study is active in six provinces (AB, BC, NS, ON, PEI, and QC) and one territory (YT). Importantly, CANVAS-COVID also collects health information from individuals not yet vaccinated for comparison as a control population.

It is important to note that all events recorded in the CANVAS-COVID surveys are self-reported and, thus, the definition of the severity of an event is determined by the participant. Events are reported at a specific time after getting the vaccine and do not mean they were caused by the vaccine. Additionally, the sample may not be representative of all Canadians.

As part of the wider Canadian Immunization Research Network (CIRN), CANVAS regularly monitors the safety of seasonal influenza vaccines. In early 2021, it pivoted to also monitor COVID-19 vaccine safety (CANVAS-COVID) in adolescents and adults, and recently extended this to children under 12 years old. The latest findings from CANVAS-COVID are updated weekly on their website.

Bettinger JA, De Serres G, Valiquette L, Sadarangani M, Muller MP, Vanderkooi OG, Kellner JD, Top KA, Isenor JE, McGeer A, Irvine M, Shulha H, Marty K. Canadian National Vaccine Safety (CANVAS) Network: Active Safety Surveillance on COVID-19 vaccines. Canadian Immunization Conference. 2021 Dec 8.