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Update Saturday April 10th: The paper, mentioned as a pre-print in a previous post, from the German group that originally described the issue has now been peer-reviewed and published in the New England Journal of Medicine...Here....A companion paper that comes, essentially, to the same conclusions from a Norwegian group is...Here.
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Pre-post note: If you would like to cut right to the chase and go to an excellent description of this rare, but serious, side effect to the AZ vaccine, as well as specific diagnosis and treatment protocols, please go directly to the Ontario Science Table's outstanding 'Science Brief'.
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As we noted previously, the European Medicines Agency's safety committee (PRAC) has been assessing reports of rare serious clotting issues in people who have received the adenovirus-based AstraZeneca/Oxford COVID-19 vaccine.
The report is now out. It is very worth reading in its entirety.
Here are some highlights:
EMA’s safety committee (PRAC) has concluded today that unusual blood clots with low blood platelets should be listed as very rare side effects of Vaxzevria (formerly COVID-19 Vaccine AstraZeneca)...
{snip}
...So far, most of the cases reported have occurred in women under 60 years of age within 2 weeks of vaccination. Based on the currently available evidence, specific risk factors have not been confirmed...
{snip}
...The Committee carried out an in-depth review of 62 cases of cerebral venous sinus thrombosis and 24 cases of splanchnic vein thrombosis reported in the EU drug safety database (EudraVigilance) as of 22 March 2021, 18 of which were fatal.1 The cases came mainly from spontaneous reporting systems of the EEA and the UK, where around 25 million people had received the vaccine...
{snip}
...One plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin (heparin induced thrombocytopenia, HIT). The PRAC has requested new studies and amendments to ongoing ones to provide more information and will take any further actions necessary.
The PRAC stresses the importance of prompt specialist medical treatment. By recognising the signs of bloods clots and low blood platelets and treating them early, healthcare professionals can help those affected in their recovery and avoid complications.
Patients should seek medical assistance immediately if they have the following symptoms- shortness of breath
- chest pain
- swelling in your leg
- persistent abdominal (belly) pain
- neurological symptoms, including severe and persistent headaches or blurred vision
- tiny blood spots under the skin beyond the site of injection
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So, the findings are similar to those we discussed last week, based on initial findings in Germany and other European jurisdictions. One important new thing is that there are now data from the UK to support this finding.
To reiterate, this is a rare condition. Specifically, there have been 86 events reported out of ~25 million vaccinated so far. Importantly, the condition is more common in women under the age of 60. A British medical oversight group has attempted to estimate the incidence rate in that specific group. They still find that it is a very rare event but emphasize that more data are required to be certain of the rate of adverse events.
As the EMA notes, it appears that the post-AZ vaccine events may be similar to a rare immunological response to heparin that causes inappropriate clotting inside the blood vessels.
Unfortunately, at this time it is not possible to tell who will respond to the AZ vaccine in this way (i.e. 'specific risk factors have not been confirmed'), other than it occurs most often in women under 60. However, a number of post-vaccination physical symptoms of concern have been identified that indicate the need for immediate medical intervention. The latter are outlined in the box above.
As we noted last week, a group in Germany with expertise in the field, including a rare heparin-induced clotting syndrome, has proposed a way to diagnose and treat the AZ vaccine-associated condition. At this time the European Medicine Agency's safety committee (the 'PRAC' quoted above) has asked for more study on this matter. However, the British Hematological Society has posted a 'Guidance on Management' protocol as has a similar German Society For The Study Of Thrombosis and Hemostasis as well as the Ontario Science Table.
In the case of the Ontario Science Table, they have outlined concrete diagnosis and treatment protocols. As noted at the top of the post, they also explain things well - it is very worth reading.
Here's hoping that we receive an update on this matter from our National Advisory Committee On Immunization so that Canadians can be confident that we are moving forward with all the best and most appropriate information and procedures possible.
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The BCCDC statement on the AZ Vaccine, which is now being offered to folks 55-65 years of age, is....here....A handout on AZ vaccine aftercare is....here.
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