Announcement

**Pathfinder** · March 31, 2021, 08:48 AM

NACI rapid response: Recommended use of AstraZeneca COVID-19 vaccine in younger adults

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Recommendation

NACI recommends that AstraZeneca COVID-19 vaccine should not be used in adults under 55 years of age at this time while the safety signal of Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT) following vaccination with AstraZeneca COVID-19 vaccine is investigated further.

Summary of rationale

Rare cases of serious blood clots, including cerebral venous sinus thrombosis, associated with thrombocytopenia have been recently reported in Europe following post-licensure use of AstraZeneca COVID-19 vaccine^Footnote1^Footnote2. Cases identified so far have been primarily in women under the age of 55 years; although cases in men have also been reported and have mostly occurred between 4 and 16 days after receipt of vaccine. This adverse event is being referred to as Vaccine-Induced Prothrombotic Immune Thrombocytopenia (VIPIT)^Footnote3. This entity is associated with the development of antibodies that "activate" platelets, which stimulate the formation of clots and result in thrombocytopenia. The mechanism of action is similar to heparin-induced thrombocytopenia (HIT). The exact mechanism by which the AstraZeneca vaccine triggers VIPIT is still under investigation. At this time, no other risk factors have consistently been identified in patients who develop VIPIT. This adverse event has not been identified following receipt of mRNA COVID-19 vaccines to date.

The rate of this adverse event is still to be confirmed. Based on information from the European Medicines Agency on March 18, 2021 it was originally estimated at approximately 1 per 1,000,000 people vaccinated with the AstraZeneca vaccine, however a higher rate of 1 per 100,000 was reported by the Paul-Ehrlich Institut in Germany^Footnote4. Additional information is currently being gathered to characterize more accurately the rate of VIPIT. Based on available information, the case fatality of VIPIT is approximately 40%, however, the case fatality may decrease with increased awareness of the adverse event and appropriate early treatment.

Following population-based analyses of VIPIT assessing risk of COVID-19 disease by age, and considering that alternate products are available (i.e., mRNA vaccines), from what is known at this time, there is substantial uncertainty about the benefit of providing AstraZeneca COVID-19 vaccine to adults under 55 years of age given that the potential risks associated with VIPIT, particularly at the lower estimated rates. As a precautionary measure, while Health Canada carries out an updated benefit/risk analysis based on emerging data, NACI recommends that the vaccine not be offered to adults under the age of 55. Adults 55 years of age and older may still be offered the AstraZeneca vaccine with informed consent, given the increased risk of hospitalization and death due to COVID-19 disease in this population^Footnote5 and since VIPIT appears to be a rarer event in that age group^Footnote6. Since the current cases have occurred primarily in women, men may be less at risk of this adverse event and could potentially have a different benefit/risk assessment, however investigations are ongoing as it is possible that the reported female predominance of VIPIT is because more women received the AstraZeneca vaccine, making it difficult to assess risk based on sex. Young healthcare workers, one of the early priority groups receiving this vaccine globally, include a higher proportion of females.

Anyone receiving the AstraZeneca COVID-19 vaccine should be informed of this potential adverse event and advised to seek immediate medical attention if they develop symptoms of thromboembolism and/or thrombocytopenia between days 4 and 20 following receipt of the AstraZeneca vaccine^Footnote3. Symptoms to be vigilant for include: shortness of breath, chest pain, leg swelling, persistent abdominal pain, neurological symptoms including sudden onset of severe or persistent worsening headaches or blurred vision, skin bruising (other than at the site of vaccination) or petechiae^Footnote3^Footnote6. In addition, healthcare professionals should be aware of VIPIT including how to diagnose and treat the condition (see Ontario Science Table guidelines^Footnote3).

Canada is expected to receive sufficient mRNA COVID-19 vaccines to fully vaccinate the population with two doses of mRNA vaccine before fall 2021. AstraZeneca COVID-19 vaccine was expected to make up a small proportion of the COVID-19 vaccines available for use in Canada; therefore, COVID-19 vaccinations will not be significantly delayed without using AstraZeneca COVID-19 vaccine in younger adults.

Based on the international data that continues to emerge regarding VIPIT following receipt of AstraZeneca COVID-19 vaccine, the precautionary principle, and Canada's expected supply of mRNA COVID-19 vaccines, NACI has made a recommendation that will continue to be reassessed based on the rapidly evolving evidence.

Given the rare but severe VIPIT events reported in Europe, mainly in women under 55 years of age, and a plausible causal mechanistic explanation, NACI has evaluated the benefit/risk ratio comparing this adverse event to the risk of COVID-19 deaths for individuals in Canada in various age strata and considering the supply of alternate COVID-19 vaccines available in Canada (mRNA vaccines). While awaiting the results from Health Canada inquiries and the overall risk assessment, NACI recommends immediately pausing the use of the AstraZeneca vaccine in all individuals less than 55 years of age in Canada.

Decisions on the type of second dose that will be offered to those individuals under 55 years of age who have been vaccinated with AstraZeneca COVID-19 vaccine will be determined based on the latest evidence and research. NACI will continue to review evidence as it emerges, including evidence on mixed COVID-19 vaccine schedules, to provide advice to public health programs on the potential for completing the series with other vaccine products.

Further information on signs and symptoms of this adverse event and treatment can be found on Health Canada's website.
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Date modified: 2021-03-29

https://www.canada.ca/en/public-health/services/immunization/national-advisory-committee-on-immunization-naci/rapid-response-recommended-use-astrazeneca-covid-19-vaccine-younger-adults.html

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Remarks from the Chief Public Health Officer on Tuesday, March 30, 2021

From: Public Health Agency of Canada

Speech

The COVID-19 pandemic continues to create stress and anxiety for many Canadians, particularly those who do not have ready access to their regular support networks. Through the Wellness Together Canada online portal, people of all ages across the country can access immediate, free and confidential mental health and substance use supports, 24 hours a day, seven days a week.

Today we?ll touch on the recent safety signal associated with the use of the AstraZeneca vaccine in adults under 55 years of age. But first, we?ll begin with an update on the current numbers and trends.

COVID-19 activity has been steadily increasing for several weeks, with a rising number and proportion of more contagious variants driving epidemic growth in many areas.

To date, over 970,000 cases of COVID-19, including 22,900 deaths have been reported across Canada. Over the past week, there have been an average of over 4,600 new cases and 26 deaths reported daily. The ongoing increase in infection rates is now playing out in our hospitals, with rising trends in severe and critical illnesses placing renewed strain on the health system. Over the past week, an average of over 2,200 people with COVID-19 were being treated in our hospitals each day representing a 6% increase over last week. Over 660 of these people were being treated in intensive care units, which is 14% higher than last week.

Most concerning is the continued increase in number and proportion of variants of concern that spread more easily and increase the risk of severe illness outcomes. Over the past week, there has been a 64% increase in new variant cases. To date, over 9,000 variant of concern cases have been reported across Canada, with the B.1.1.7 variant accounting for over 90%. This includes 8,381 B.1.1.7 variants, 358 P.1 variants, and 270 B.1.351 variants reported to date in Canada. New variant case numbers represent the tip of the iceberg as there are thousands more cases that have screened positive for problematic mutations.

Yesterday, Health Canada issued a statement in relation to new data on additional cases of a rare type of blood clot, known as Vaccine-Induced Prothrombotic Immune Thrombocytopenia (or VIPIT), which occurred following the administration of the AstraZeneca COVID-19 vaccine in several European countries. To date, no cases of VIPIT have been reported in Canada. Nevertheless, as the data on these additional cases could change the risk benefit assessment, Health Canada, as regulator, has put in place additional terms and conditions on the authorization of AstraZeneca vaccines in Canada. In the interim, Canada?s National Advisory Committee on Immunization (NACI) has recommended to pause the use of the AstraZeneca vaccine for people aged under 55 years, pending a full risk assessment by Health Canada. Chief Medical Officers of Health have considered NACI?s recommendations and have issued a statement outlining a unified decision to take this precautionary measure.

I know this is another difficult development in the seemingly never ending twists and turns of this pandemic, but there is a point of grace. I couldn?t have said it better, so I would just like quote Dr. Menaka Pai, Associate Professor of Hematology & Thromboembolism at McMaster University who notes, ?Strong global vaccine safety surveillance rapidly picked up this rare and serious adverse event. Collegiality, academic rigour, transparency, and medical science will help us manage it.?

As Spring brings warmer weather and as important religious observances such as Passover, Easter, Vaisakhi and Ramadan are upon us, we too must do our best and remember our duty to protect one another. COVID-19 activity levels are different depending on where you are in Canada but there is a risk of introduction and rapid acceleration of cases everywhere.

Please continue to follow local public health recommendations, stick to the safer ways we?ve learned to celebrate during COVID-19 and save gatherings for a better time in the future.

Despite the hurdles, we are getting closer everyday and we?re stronger and more united for it.

Read my backgrounder to access COVID-19 Information and Resources, including information on vaccination and ways to reduce your risk of infection and spreading the virus to others.

https://www.canada.ca/en/public-health/news/2021/03/remarks-from-the-chief-public-health-officer-on-tuesday-march-30-2021.html

**Pathfinder** · April 13, 2021, 04:03 PM

Translation Google

AstraZeneca: a first case of thrombosis in Quebec

VINCENT LARIN
Tuesday, April 13 2021 13:10
UPDATE Tuesday, April 13, 2021 4:23 PM

The Ministry of Health confirmed on Tuesday that a first case of thrombosis occurred in Quebec in the last days following the administration of an AstraZeneca vaccine.

?The person was taken care of by the health and social services network and received the care appropriate to their condition. She is now recovering at her home and there is no fear for her life, ?said the Ministry of Health and Social Services (MSSS) in a press release in which it seeks to reassure the population.

The government welcomed the rapid management of the inoculated person thanks to its "effective protocols in place" to detect cases of thrombocytopenia with thrombosis.

"Cases of thrombosis with thrombocytopenia are considered to be a possible complication of the vaccine, but remain very rare, ie around 1 case in 100,000 vaccines administered," recalled the MSSS, which continues to estimate that the risk posed by COVID- 19 is by far superior to that of thrombosis.

The federal government has confirmed that it is aware of the matter. "Health Canada is aware of this case, which will be considered as part of its ongoing review of the safety of AstraZeneca vaccine and COVISHIELD vaccine, and the risk of rare blood clots associated with low platelet counts, ?said Ottawa.

The announcement comes as the United States announced Tuesday the suspension of Johnson & Johnson's vaccine , also for potential cases of thrombosis. Canada, for its part, will not suspend imports of this vaccine for the moment, the first doses of which are expected at the end of April.

AstraZeneca's vaccine is undergoing several reviews around the world after being linked to cases of blood clots and thrombosis.

Consequently, the Quebec government is currently limiting its use to people aged 56 and 79. Walk-in clinics have recently been offered to sell doses of this vaccine.

https://www.journaldemontreal.com/2021/04/13/astrazeneca-un-premier-cas-de-thrombose-survenu-au-quebec

Announcement

Immunization committee to recommend provinces stop giving AstraZeneca vaccine to those under 55: sources

Immunization committee to recommend provinces stop giving AstraZeneca vaccine to those under 55: sources

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