Inadvertant intravenous injections

Intravenous Injection of Coronavirus Disease 2019 (COVID-19) mRNA Vaccine Can Induce Acute Myopericarditis in Mouse Model

https://academic.oup.com/cid/advance-article/doi/10.1093/cid/ciab707/6353927
Background

Post-vaccination myocarditis and pericarditis reported after coronavirus mRNA vaccines.

The effect of accidental intravenous injection of this vaccine on the heart is unknown

Methods in mice

Compared difference between i.m. and i.v. injection of vaccine

Clinical manifestations

Histopathological changes

Tissue mRNA expression

Serum levels of cytokines and troponins

With normal saline (NS) control

Results

Intravenous SARS-CoV-2 mRNA Vaccine Administration Induced Grossly Visible Pathology in Heart

Only IV group developed histopathological changes of myopericarditis

Evidenced by cardiomyocyte degeneration

Apoptosis

Necrosis with adjacent inflammatory cell infiltration

Calcific deposits on visceral pericardium

But

Evidence of coronary artery or other cardiac pathologies was absent

Spike antigen (immunostaining) occasionally found in infiltrating immune cells of the heart

And in cardiomyocytes and intracardiac vascular endothelial cells

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

Numerous inflammatory cytokines found in cardiac tissue

(interleukin (IL)-1β, interferon (IFN)-β, IL-6, and tumor necrosis factor (TNF)-α)

in the IV group but not the IM group

compatible with presence of myopericarditis in the IV group

Ballooning degeneration of hepatocytes was consistently found in the IV group.

All other organs appeared normal.

Conclusions

In vivo evidence that inadvertent intravenous injection of COVID-19 mRNA vaccines may induce myopericarditis.

Brief withdrawal of syringe plunger to exclude blood aspiration may be one possible way to reduce such risk.

Both Pfizer/BioNTech and Moderna have clearly stated that their vaccines should only be given via IM route

Current CDC and WHO guidelines no longer recommend precautionary measures during IM vaccine administration

The CDC Pink Book 2020 and WHO
2015 position paper have recommended against aspiration prior to vaccine injection so as to minimize pain

Deltoid to the vastus lateralis?

Our study indicates that IV injection of vaccines might partially contribute to this clinical phenotype,

thus warranting a reconsideration of the practice of IM injection without aspiration,

which carries the risk of inadvertent IV injection.

Thrombocytopenia in mice reported in 2006

Blood, (2006)

https://ashpublications.org/blood/article/109/7/2832/125650/Adenovirus-induced-thrombocytopenia-the-role-of

All mice received virus through a single tail vein injection

Thrombocytopenia has been consistently reported following the administration of adenoviral gene transfer vectors.