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Comment by UncleOxidant | Hacker News Reader

John Campbell suggested on his video the other day that perhaps this is happening because some injectors are not aspirating. What that means is that when an intramuscular injection is given you want to ensure that it goes into the muscle and not into a vein. So the proper way to do this is for the person doing the injection to first pull out the syringe (after it's been stuck into the arm) a bit to make sure there's no blood coming out. Then if not, the vaccine is pushed in. If blood is seen then a new site has to be chosen. Apparently Denmark has included aspiration in their directions for usage of the AZ vaccine.

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Medical professionals are often taught these days that aspiration is not necessary for IM injections, particularly in commonly used sites such as the delts.

From the CDC [1]: Aspiration before injection of vaccines or toxoids (i.e., pulling back on the syringe plunger after needle insertion but before injection) is not necessary because no large blood vessels are present at the recommended injection sites

[1] https://www.cdc.gov/vaccines/hcp/acip-recs/general-recs/admi...

This lines up exactly with what Dr. Daniel Griffin talked about in the most recent clinical update podcast for TWIV [1]. Apparently aspirating makes the shot more painful, because the needle is in the body longer, and serves no benefit as long as the vaccinator is putting it in the right location.

1: https://www.microbe.tv/twiv/twiv-741/ (towards the end)

"no large blood vessels are present at the recommended injection sites"

That's a bold statement. Sure, no large blood vessels may be present at the recommended injection site on an average human, but it's well known there is more divergence in anatomy than they necessarily teach about in primary school, and vaccines are supposed to go in basically everyone.

Still, even if it gets close to a small vessel it might be problematic

Maybe we'll need to do it for AZ. Or maybe subcutaneous?

That's interesting to know. When I got my Pfizer jab, the lady said "oops, I did it wrong" and blood came out. She didn't jab me again though and I just assumed it was good to go. Should she have done it again at a different site? I was told elsewhere that it doesn't make the vaccine any less effective, but I'm curious what others on here think now...

As I understand it the concern isn't effectiveness so much as potential for side effects. An intramuscular injection is meant to stay pretty much in a small area of muscle tissue. If it goes into the vein the vaccine then travels into tissues all over the body.

That’s not really true, we give lots of drugs IM because the muscle is highly vascular so it generally shoots out all over the body really quickly. Ie want to take down a patient with Ice (crystal meth) induced psychosis? IM. Also, it’s hard to miss most of the time.

If you want something to sit around for a long time, you go for less vascular areas. (Ie insulin for diabetics, subcut abdominal fat)

IM is preferred because of the vascularity which helps in the immune response (ie quick immune response, antigen distributed around the body) as well as any immune reaction confined to the muscle rather than, say the skin. (0) is a quick and dirty on mechanisms of administration.

To your earlier point about ‘into’ a vein, I’d never heard of Dr Campbell before you mentioned him, he seems to have great credentials, but I can’t easily explain why an accidental IV administration of an IM vaccine would cause CVST, my gut is that it’s a bit of a hand wave but who knows.

(0) https://www.forbes.com/sites/quora/2017/11/07/why-arent-vacc...

IV injection of adenovirus gene therapy vectors is well known to cause thrombocytopenia.

Right, thanks, I wasn’t aware.

Time periods seem off (5-14hrs) in mouse models compared to what’s being seen here though, which seems more like an immune reaction rather than a response to the antigen/delivery system

That makes no sense of course. You’re innoculating the whole body, especially bone marrow and lymph nodes, not a small area of muscle.

If this were the case it would be odd that this is happening a.) in a consistent subset of women 18-38 b.) that it would emerge in a 1-shot regimen rather than a 2-shot regimen, because it would seem more likely that any one individual would experience this more frequently with 2 chances for human error rather than 1

The Pfizer & Moderna 2-shot vaccines use mRNA instead of an adenovirus vector. The AZ vaccine is 2 shot, but also uses a similar adenovirus vector - the bloodclot issue has also been seen in the AZ vaccine which has led to some countries in Europe not allowing it for women under 60.

I would assume the guidelines for aspirating would be the same across all of these vaccines, though? If so the original point still stands regardless of adenovirus vs. mRNA

Yes, we know that. But what does adenovirus vs mRNA have to do with aspirating an injection? Does the adenovirus become more dangerous when accidentally placed in a blood vessel?

with only 6 people you can't really say that since it's such a tiny sample size. If it's 6 women then you're starting to get to a pattern worth testing.

Injecting IM solution into a blood vessel is excruciating and you and the provider would notice it immediately if it happened. It is likely to cause an embolism and possibly kill you, but I don't think it would be unnoticeable and then cause a thrombus multiple days later.

There are also not a lot of major vessels near common injection sites, for this reason. It's possible and rather common to nick a surface capillary or something, and those can bleed quite a lot, but a vein or artery would be totally different. Swelling, horrible pain, likely a cough.

Source: inject myself with intramuscular estrogen every week.

hah, I inject myself with estrogen subcutaneously. it gets absorbed quicker which causes peaks and troughs, but I get to use a smaller needle (25g x 5/8") and I don't have to worry so much about bruising or locating the right sites.

I should ask about subq. My current regimen gives me a lot of anxiety, even though I know it's pretty safe.

Any theory on why this is occurring needs to have a solid explanation for why women under 55 are suffering this effect more than anyone else. Does John Campbell have one?

Perhaps because younger veins and capillaries are easier to accidentally inject into?

https://www.sciencedaily.com/releases/2006/10/061031141826.h...

> Apparently Denmark has included aspiration in their directions for usage of the AZ vaccine.

Great, so not only will I have to wait 2-3 months to get vaccinated..

They'll also stick the needle in and pull out a few times just to sure I'm really feeling it!!!

Sorry, but I really hate needles :/

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