Precise cause and effect haven’t been isolated at this time, but the working theory is that it’s polyethylene glycol, which is also commonly used in foods, cosmetics, and other medications. However, it’s been show to cause rare allergic reactions in previous use cases.
The differences in how PEG is used in the Moderna and Pfizer lipid shell formulations likely accounts for the variance in reaction frequency (1 per 90,000 with Pfizer, 1 per 400,000 with Moderna).
PEG is highly correlated with neurological issues like tics and ocd in children prescribed it long term for constipation. The pharma co tells the pediatricians that the little balls of plastic stay in the digestive tract from mouth to anus and have no way of getting into the bloodstream or brain. That is a lie. Doctors pass on to their patients’ parents this lie.