Question Period Note: ADVERSE REACTIONS

• Given recent reports of blood clots following the use of viral vector COVID-19 vaccines (COVISHIELD, AstraZeneca, Janssen) in Canada and internationally, and international reports of myocarditis after mRNA vaccination, What is the Government doing to ensure vaccine safety, including monitoring for adverse reactions to the COVID-19 vaccines?
• How is the Government making its decisions on the safe use of viral vector and mRNA vaccines?

KEY MESSAGES
• The safety and effectiveness of vaccines used in Canada is our government’s highest priority.
• Canada’s monitoring systems for adverse events following immunization rapidly detect possible safety issues and investigate them thoroughly. The regulator takes action in line with the risks and benefits of the vaccine.
• Reports of heart inflammation (myocarditis or pericarditis) following vaccination with mRNA vaccines have been reported internationally. Health Canada and the Public Health Agency of Canada are closely monitoring this situation.
• Evidence is limited at this time, so monitoring and engagement with international health authorities ensures that Canada is receiving relevant information on this matter.

IF PRESSED…
• Health Canada and the Public Health Agency of Canada also continue to closely monitor reports of rare but serious cases of blood clots associated with low levels of blood platelets following vaccination with AstraZeneca/COVISHIELD COVID-19 vaccines and reports from the US related to the Janssen vaccine.

BACKGROUND
Safety is a central consideration for any health product, including vaccines. Canada’s rigorous regulatory system ensures that vaccines are safe, effective and of high quality before they are authorized. However, no health product is completely risk-free.
Adverse events following immunization (AEFI)
An adverse event may occur after a person has been vaccinated. The majority of adverse events are mild reactions (e.g., pain, redness, swelling at the injection site, muscle soreness, mild headache), although serious and rare events can occur (e.g., allergic reaction). However, as the WHO states: “The fact that a vaccine was administered within a reasonable time period of the occurrence of an event does not automatically suggest that the vaccine caused or contributed to the event”.
Post-market COVID-19 vaccine safety monitoring
Post-market vaccine surveillance is required to monitor and understand how vaccines behave in the entire population and their real-world impact. Vaccine safety surveillance is critical for rapidly detecting and responding to safety issues, ensuring that the benefits of the vaccine continue to outweigh the risks and supporting vaccine uptake by building public confidence in Canada’s immunization programs.

Canada has a well-established vaccine safety surveillance system that is a collaboration between provinces and territories, PHAC, Health Canada, and vaccine manufacturers. Manufacturers are required to report serious adverse events to Health Canada as the national regulatory authority, as well as submit regular summaries of global safety information. In addition, PHAC receives and reviews reports of adverse events following immunization from provinces and territories (P/T) through the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS). This system has been enhanced to support the rollout of COVID-19 vaccines, to expedite the timeliness and sharing of information with partners, and public reporting of adverse events.
To improve safety surveillance further, the Government of Canada provides funding to the Immunization Monitoring Program ACTive (IMPACT) network, a paediatric, hospital-based network that reports adverse events to PHAC, and Canadian Vaccine Safety (CANVAS) Network which provides weekly reports to PHAC and P/T health authorities.
Thrombosis and Thrombocytopenia Syndrome (TTS)
Health Canada and PHAC continue to closely monitoring international reports of thrombosis and thrombocytopenia following immunization with viral vector vaccines - AstraZeneca and COVISHIELD vaccines (Europe) and Janssen (US). Evidence thus far suggests an association between these vaccines and very rare events involving serious blood clots and low levels of blood platelets.
On April 14, 2021, HC updated the AstraZeneca and COVISHIELD vaccines’ product information and issued a public advisory to ensure there was awareness about this risk among health professionals and vaccine recipients. Health Canada will continue to monitor information from the manufacturers and international regulators about this safety issue.
PHAC has received reports of individuals in Canada who have experienced blood clots with low numbers of platelets following immunizations with the COVISHIELD (the Serum Institute of India version of the AstraZeneca COVID-19 vaccine) and AstraZeneca vaccine. These reports are rare, and they show that Canada’s vaccine safety monitoring system works.
To support clinicians in identifying, diagnosing and treating people with this rare side effect, Thrombosis Canada, with agreement from many provincial thrombosis leaders, and in collaboration with PHAC, has developed and disseminated clinical guidance. In addition, PHAC, Thrombosis Canada, and the National Collaborating Centre for Infectious Diseases have delivered a webinar to inform health care providers on the treatment and reporting of this condition.
On April 23, 2021 and May 3, 2021 respectively, NACI updated its recommendations on the use of authorized COVID-19 vaccines to incorporate its analysis of thrombosis (blood clots) with thrombocytopenia (low platelets) following vaccination with AstraZeneca and Janssen. At this time and based on current evidence, NACI recommends that the AstraZeneca and Janssen vaccines may be offered to individuals 30 years of age and older without contraindications if the individual does not wish to wait for an mRNA vaccine and if benefits outweigh the risk.
NACI’s updated recommendation is informed by Health Canada’s safety assessment; the most up-to-date domestic and international evidence and guidance on managing people who develop thrombosis and thrombocytopenia following vaccination, including updated rates and risks; the availability and supply of mRNA vaccines in Canada; the rapidly changing epidemiology of COVID-19 in Canada, including the circulation of variants of concern; and a comprehensive analysis of ethics, equity, feasibility and accessibility. NACI assessed the risk of developing and dying from thrombosis with thrombocytopenia following vaccination compared to COVID-19 ICU admissions and deaths that could be prevented by an early dose of the vaccine under various COVID-19 incidence rates.
NACI continues to evaluate the evolving vaccine landscape in Canada and potential safety signals, and will update guidance as needed.

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