All the vaccines are supposed to be Intra-muscular (IM), not Intravenous (IV). But a needle going into a muscle can sometimes end up in a vein. So fergoodnesssake, why aren’t we taking the 10 extra seconds to do an injection properly and reduce some of the worst side effects?
Anatomy varies. In an accidental IV injection the dose will be dropped straight into the blood supply, and within minutes will be spread throughout the body, potentially ending up in tissues like the heart, ovaries, or pancreas, where it is not designed to go. If heart cells, for example, make the virus spike and display it on their surface, it’s quite understandable if our immune systems think that look foreign, and generate a reaction. That’s myopericarditis.
Not all veins are identical
Spread the message about “aspiration”. This used to be standard practice for most IM injections but has been dropped over the last couple of decades.
To aspirate, a nurse would put the needle in, then briefly pull back on the syringe. If the end of the needle is in a blood vessel that brief suction will pull blood into the chamber. If that happens the whole syringe, needle, everything should be retracted and tossed in the bin.
Two studies now suggest that accidental IV injections may be responsible for increasing the risk both of myocarditis and blood clots.
A study in mice by Can Li showed that the mice injected “IM” did not develop myocarditis, only the mice injected intravenously did. The markers of cardiac inflammation were also raised.
The histological changes of myopericarditis after the first IV-priming dose persisted for 2 weeks and were markedly aggravated by a second IM- or IV-booster dose. Cardiac tissue mRNA expression of interleukin (IL)-1β, interferon (IFN)-β, IL-6, and tumor necrosis factor (TNF)-α increased significantly from 1 dpi to 2 dpi in the IV group but not the IM group…
Bizarrely, some were arguing that myocarditis is only a 1 in 50,000 thing and aspirating slows vaccinations, and thus it might be worse to aspirate when it makes no difference to 49,999 people. I’m guessing most people would think it was 10 seconds well spent.
It’s encouraging that the second paper seems to have figured out the reason for the rare but deadly TTS clots. These are a problem especially with the Astrazenica and Johnson and Johnson vaccines which are adenovirus vaccines. The riskiest time is 5 to 24 days after the first dose when antibodies may form against Platelet Factor 4. The paper, Baker et al, suggests the vaccine leaks out through minor capillary injuries. But neither that, nor the theory about a lack of aspiration explain why the second dose is not just as much a problem. The paper doesn’t mention injection technique, but it seems odd, if the problem is the vaccine leaking out through damaged blood vessels, why it wouldn’t be so much worse with a poorly done injection.
Judging by comments around the traps, people who want an aspirated injection may need to work in advance to find a nurse who knows how it’s done and is willing to do it.
h/t David Maddison
TTS = thrombosis with thrombocytopenia syndrome
Can Li et al (2021) Intravenous Injection of Coronavirus Disease 2019 (COVID-19) mRNA Vaccine Can Induce Acute Myopericarditis in Mouse Model, Clinical Infectious Diseases, ciab707, https://doi.org/10.1093/cid/ciab707
Baker et al (2021) ChAdOx1 interacts with CAR and PF4 with implications for thrombosis with thrombocytopenia syndrome, Science Advances • 1 Dec 2021 • Vol 7, Issue 49 • DOI: 10.1126/sciadv.abl8213
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December 7, 2021 at 10:50AM