Safety Margin for Plasma Hyperviscosity in Cardiovascular Disease Patients after COVID-19 Vaccination for Thrombosis Prevention

Dear Editor,

We read the article entitled “Vaccinating Patients with Heart Disease Against COVID-19: The Reasons for Priority” with great interest. COVID-19 vaccination is accepted as the best way for preventing the disease, but data on its safety are still warranted. An important problem found after COVID-19 vaccination is the rheological change causing intravascular clotting and thrombotic complications. Changes in blood viscosity after COVID-19 vaccination have been confirmed. A vaccine can induced rapid production of antibody, which is a protein that can increase plasma viscosity by an estimated 2.4 centipoise (cP) from normal values in healthy person.^, The problem might occur if changes in plasma viscosity reach levels above 5 cP, considered a hyperviscosity state.

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