Change of blood viscosity after COVID-19 vaccination: estimation for persons with underlying metabolic syndrome.

The COVID-19 vaccine is a new vaccine aiming at control of COVID-19 pandemic. This new vaccine is useful for pandemic management, however, an important consideration is on its safety. Thrombosis is a problem might occur after COVID-19 vaccination and the increased blood viscosity is a pathomechanism. Here, the authors estimate on blood viscosity change after COVID-19 vaccination for vaccine recipient with underlying metabolic syndrome. Based on mathematical modelling and simulating technique, the authors estimate the change of blood viscosity after COVID-19 vaccination for persons with underlying metabolic syndrome. According to the estimation, blood viscosity in a healthy person is estimated 2.7 times higher than the normal value while blood viscosity in person with the underlying metabolic syndrome is estimated 2.99 times higher than the normal value. Based on this preliminary report, a more increased blood viscosity level is detected in vaccine recipients with the underlying metabolic syndrome. Monitoring of the blood viscosity problem among a vaccine recipient who has metabolic syndrome is recommended.