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COVID-19 VACCINES AND THE REPORTED RISK OF ASSOCIATED BLOOD CLOTS

April 22, 2021 | Ramadan 10, 1442 AH


In the name of Allah, the Most Gracious, the Most Merciful

Abundant Peace, Blessings and Salutations upon the Prophet Muhammad


The CMCTF published its statement on the AstraZeneca-Oxford and Covishield COVID-19 Vaccines on March 11, 2021. Since then, this and other vaccines have been the focus of many headlines given the extremely rare association with serious blood clots, now termed Vaccine-Induced Prothrombotic Immune Thrombocytopenia, or VIPIT. The identification, reporting and response to this and any potential future concerns is a testament to the robust post-vaccination surveillance systems in place that have been able to identify such rare events.


On March 29th, the National Advisory Committee on Immunization (NACI) advised the AstraZeneca-Oxford vaccine to only be offered to those aged 55 years and older due to early reports of VIPIT in mostly young women. After reviewing updated reports from across the country and around the world, Health Canada has recommended expanding the use of this vaccine to younger age groups again.


VIPIT (Vaccine-Induced Prothrombotic Immune Thrombocytopenia)


Based on the latest evidence, VIPIT is extremely rare and occurs in anywhere between 1 out of 250,000 (0.0004%) to 1 out of 1 million people (0.0001%), depending on the COVID-19 vaccine and patient’s age. It usually presents with blood clots in the brain called Cerebral Venous Sinus Thrombosis (CVST), although it can also cause blood clots in arteries or veins in other parts of the body, such as the lungs, limbs or abdomen. It typically occurs 4-20 days after the vaccine and is the result of an exaggerated immune response in select individuals who have pre-existing rare antibodies. It is important to be aware of how VIPIT may present, so that everyone can self-monitor their symptoms after receiving their COVID-19 vaccine (see below). Fortunately, there are treatments available and individuals with a personal or family history of blood clots are not considered to be at higher risk of developing VIPIT than the general population.


Putting Risk Into Perspective


While the risk is certainly present and warrants attention, it is important to contextualize this with other risks that we encounter and accept on a daily basis. For example, the risk of blood clots occurring on their own by chance (0.13%), side effects from medications that we may take for other health conditions or even a car accident while driving, are much higher than the risk of blood clots from the COVID-19 vaccine, and yet are acceptable to most of us. We have seat belts and airbags to mitigate risks in car accidents, and by preventing serious illness, the COVID-19 vaccines help significantly reduce the much higher risk of blood clots (14.7%) in hospitalized patients with COVID-19. Finally, the risk of VIPIT is much less than that of developing COVID-19 itself, especially within hotspot regions with this third wave of rising infections, hospitalizations and deaths across the country.


As such, the benefits of all approved COVID-19 vaccines continue to far outweigh any identified associated risks. They all offer excellent protection against severe illness, hospitalization, and death due to COVID-19. In line with Canadian and international expert body recommendations, we support informed decision-making and continue to strongly recommend receiving the first COVID-19 vaccine available to you, to help reduce the burden of COVID-19 in our communities. As intramuscular injections, it is permissible to receive any of the COVID-19 vaccines while fasting during Ramadan and eligibility criteria for some vaccines may change as the situation evolves.

The AstraZeneca-Oxford, Covishield and all other approved COVID-19 vaccines continue to be recommended for all eligible Canadians and Canadian Muslims. Please discuss specific questions or concerns related to your medical history with your healthcare provider. Within the first 20 days of your vaccine, monitor closely for: Tiny red or purple spots under the skin, headache, seizures, blurred vision, chest pain, shortness of breath, abdominal pain, confusion, or leg swelling, tenderness, or coldness. Please seek medical attention urgently if you experience any of these symptoms after receiving a COVID-19 vaccine.

Disclaimer


Information is quickly changing in this pandemic, and as we learn more, recommendations and guidelines may change or be updated. Detailed official information regarding the COVID-19 vaccines is available from the National Advisory Committee on Immunization (NACI).


Guiding Resources


AstraZeneca COVID-19 vaccine use in younger adults: NACI recommendation

Ontario Science Table - VIPIT following AstraZeneca COVID-19 Vaccination: Interim Guidance for Healthcare Professionals in the Outpatient Setting

Thrombosis Canada - AstraZeneca COVID-19 Vaccine Statement April 2

Thrombosis (Blood Clots) and COVID-19 Vaccines - FAQs

Cerebral venous thrombosis: a retrospective cohort study of 513,284 confirmed COVID-19 cases and a comparison with 489,871 people receiving a COVID-19 mRNA vaccine

AstraZeneca's COVID-19 vaccine: EMA finds possible link to very rare cases of unusual blood clots with low blood platelets | European Medicines Agency



COVID-19 Vaccines and Blood Clots - CMCT
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