Although researchers found a significantly higher incidence of blood clots in people who were infected with COVID, the incidence of blood clots following vaccines was still much higher than the background incidence of 0.41, a strong signal that the vaccines pose this specific risk.

“These findings are consistent with what we know about how vaccine-induced spike proteins can on their own cause cell signaling through interactions with the ACE-2 receptors,” said Lyn Redwood, RN, MSN, president emerita of Children’s Health Defense. “When this happens, it can result in inflammation and a host of other potentially pathological events in the epithelial lining of the blood vessels which can then trigger pro-inflammatory cytokines capable of activating coagulation systems and down-regulating anticoagulant pathways resulting in clot formation.”

Which is what I thought might be the case. There are some symptoms of COVID-19 like pneumonia that can only be caused by the live virus: if the virus is not destroying lung cells through its reproductive process, the destroyed cells will not cause your lungs to fill up with fluid. But if a certain COVID-19 protein causes harm to your body either directly or by triggering a harmful immune response then you can't use that protein to train your immune system without producing that same symptom.