Five things to know about COVID-19 vaccine safety in Canada
COVID-19 vaccination has brought up questions about vaccine safety. Here, five high yield points have been reviewed about vaccine safety in Canada. First, assessment and monitoring of vaccine safety is a continuum through its life cycle, with many stakeholders involved. COVID-19 vaccines marketing authorization by Health Canada means that there is sufficient evidence of their safety, efficacy, and quality in lab studies and clinical trials. However, sufficient evidence does not guarantee that rare serious or unexpected adverse effects would not occur. Therefore, Health Canada monitors vaccines’ safety and quality after marketing in collaboration with vaccine manufacturers. Moreover, vaccine providers’ safety concerns reported to local public health units are aggregated at provincial-territorial agencies and nationally at the Public Health Agency of Canada for further assessment. In addition, The World Health Organization monitors vaccines’ safety internationally1.
Second, adverse events following immunization (AEFI) may not be causally related to vaccines. AEFI is an unfavourable sign, symptom, laboratory finding, or disease following vaccination. It cannot be explained by a patient’s medical history or medications. AEFI could be related to the vaccine (e.g. anaphylaxis), vaccine quality defect, vaccine handling or administration errors, immunization triggered stress (e.g. vasovagal syncope) or merely a coincidence2.
Third, vaccine providers should prevent, diagnose, and respond to AEFIs promptly. A vaccine is rarely contraindicated3, e.g. in a history of anaphylactic reaction to a previous dose of the same vaccine or one of its components. Patients should be observed after vaccination for initial anaphylaxis symptoms and promptly receive epinephrine (0.01 mg/kg, max 0.5 mg, IM in the mid-anterolateral thigh in adults and 0.3 mg in children)4.
Fourth, all serious and unexpected AEFIs must be reported, regardless of certainty about causality. Physicians, nurses, and pharmacists must report serious and unexpected AEFIs as per local or provincial protocols. In some Canadian jurisdictions, AEFI reporting is required by law. Serious AEFI could be life-threatening, require hospitalization or medical intervention, or lead to significant disability or congenital anomaly. Unexpected AEFIs are those not included in the product monogram1.
Finally, counselling has a vital role in vaccine uptake. Patients consistently rank healthcare providers as their most trusted source for vaccine information. Providers can respond to vaccine hesitancy by listening to and understanding patients’ concerns, being transparent about the latest risks and benefits and providing reassurance of a robust vaccine safety system in Canada. Providers may revisit the vaccine conversation by offering another appointment or suggesting additional reliable sources. Also, barriers such as access to healthcare should be addressed5.
I declare no conflict of interest.
Dr Mehdi Aloosh is public health and preventive medicine chief resident at McMaster University. He completed his family medicine residency at McMaster University and two Masters degrees in epidemiology and surgical education at McGill University.
References
1. Government of Canada. Vaccine safety and pharmacovigilance: Canadian Immunization Guide 2019 [Available from: https://www.canada.ca/en/public-health/services/publications/healthy-living/canadian-immunization-guide-part-2-vaccine-safety/page-2-vaccine-safety.html?=undefined.
2. Organization WH. Global manual on surveillance of adverse events following immunization. 2014.
3. Chu DK, Abdurrahman Z. Vaccine allergy. CMAJ. 2019;191(14):E395-E.
4. Fischer D, Vander Leek TK, Ellis AK, Kim H. Anaphylaxis. Allergy, Asthma & Clinical Immunology. 2018;14(2):54.
5. Leask J, Kinnersley P, Jackson C, Cheater F, Bedford H, Rowles G. Communicating with parents about vaccination: a framework for health professionals. BMC Pediatr. 2012;12:154-.
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