# AstraZeneca approval in the US

**URL:** <https://boards.straightdope.com/t/astrazeneca-approval-in-the-us/937911>\
**Category:** The Quarantine Zone\
**Tags:** covid-quarantine\
**Created:** [March 15, 2021, 4:30am UTC](https://boards.straightdope.com/t/astrazeneca-approval-in-the-us/937911 "2021-03-15T04:30:21Z")\
**Posts on this page:** 1\
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**Author:** ![eschrodinger](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschrodinger/32/122_2.png) [@eschrodinger](https://boards.straightdope.com/u/eschrodinger)\
**Post date:** [May 6, 2021, 5:32pm UTC](https://boards.straightdope.com/t/astrazeneca-approval-in-the-us/937911/393 "2021-05-06T17:32:22Z")

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Some real numbers based on national healthcare systems’ ability to find specific events. Denmark and Norway have calculated the rates of blood clots in general and CVST events in correlation with receiving the first shot of the AZ vaccine, and subtracting the background rate.

They found 2.5 CVST cases per 100,000 AZ first shots.

[https://www.reuters.com/business/healthcare-pharmaceuticals/denmark-norway-study-finds-slightly-raised-blood-clot-rates-after-astra-covid-2021-05-05/](https://www.reuters.com/business/healthcare-pharmaceuticals/denmark-norway-study-finds-slightly-raised-blood-clot-rates-after-astra-covid-2021-05-05/)

> [@](#):
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> The BMJ study looked at 280,000 18-65 year-olds in Denmark and Norway who had a first dose of the AstraZeneca vaccine between the start of February and March 11.
> 
> Using national health records, the researchers identified rates of events such as heart attacks, strokes, deep vein blood clots and bleeding events within 28 days of receiving a first vaccine dose, and compared them with expected rates in the general populations of Denmark and Norway.
> 
> Results showed 59 blood clots in the veins, compared with 30 expected, equating to 11 excess events for every 100,000 vaccinations. The researchers said this included a higher-than-expected rate of rare brain blood clots, known as cerebral venous thrombosis, at 2.5 cases per 100,000 vaccinations.

As I’ve mentioned before, I’m not suggesting that people should not get the AZ vaccine, but accurate information is crucial to informed consent, and it should also inform the medical recommendations of doctors as to which vaccine is recommended for which demographic groups.

This rate information will change the risk/benefit ratios that were so quickly produced, which said only very young people in low transmission areas would be better off waiting for a different vaccine. Presumably that equation is different if the CVST rate is more like 1/40,000 than 1/100,000. Particularly if it can be further narrowed down by demographics.

And, of course, as I’ve also previously mentioned, some places have supplies of other vaccines, so that it’s just a matter of allocating that vaccine to those at highest risk from the AZ vaccine, with no one delaying vaccination.

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