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Comment by nradov | Hacker News Reader

An animal study found that aspiration during injection could reduce the risk of vaccine induced myocarditis. It hasn't been reproduced in humans but this seems like something worthy of further research.

https://academic.oup.com/cid/advance-article/doi/10.1093/cid...

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Why would the aspiration risk be significantly different between the two mRNA vaccines?

Moderna dose is 100mcg whereas Pfizer is 30mcg. This is probably why Moderna has higher risks of myocarditis but this is just my guess.

Can you define 'aspiration' in this case? The link is rather dense to the layperson.

It is apparently a means to double check and make sure you are injecting into a muscle and not into a blood vessel by seeing if you can draw blood at that site before you actually inject anything.

https://askinglot.com/what-does-it-mean-to-aspirate-an-injec...

Aspiration is pulling back the syringe plunger prior to injection to ensure the needle tip is in the correct tissue and not in a vein. This isn't typically done for COVID-19 vaccinations, and there is some controversy in medical circles about whether this should be a standard procedure.

https://f1000research.com/articles/3-157/v3

I saw a statistic of Denmark (who are aspirating) vs Norway (who aren't), and vaccine complications[0] were something like 1 in 25.000 in Denmark vs 1 in 15.000 in Norway[1], so there was a clear difference.

[0] Or myocarditis specifically?

[1] Don't quote me on these numbers, they are ballpark numbers from my memory

isnt that backwards from the expectation?

Yes you're right, my bad, edited (switched the numbers around).

Would make totally sense, as a possible mechanism -- and its remedy -- of how the heart would be affected.

Sorry... what? what do you mean?

The vaccine is intended to be an intramuscular injection. The risk of myocarditis is possibly linked to an accidental intravenous injection. With aspiration, the person performing the injection has a chance to detect that they hit a blood vessel instead of the muscle and try again.

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