Clots form and dissolve in small quantities in the body all the time. Occasionally the amount is large and leads to pulmonary embolism and death, without a vaccine being given. Inflammatory chemokines can slightly shift this balance. Immunization leads to an inflammatory response, and any inflammation shifts the clotting balance. This is an expected side effect. The degree of this inflammation varies in different people and varies with the severity of the inflammation. Most importantly, the benefit of protection against COVID OUTWEIGHS the small increase in clotting risk.