No conflict of interest.Dear Editor, we would like to share ideas on ‘Multisystem inflammatory syndrome in a male adolescent after his second Pfizer‐BioNTech COVID‐19 vaccine
’. Chai et al. noted that ‘Multisystem inflammatory syndrome (MIS) in children (MIS‐C) is a complication of the severe acute respiratory syndrome co….. SARS‐CoV‐2 vaccines, especially in males aged 12–17 years.
’ Adverse effect of COVID‐19 vaccine is the present clinical consideration in clinical pediatric. The present case is an example. The exact cause of MIS is not yet clarified. The process might be immunopathological process similar to pathogenesis of MIS following COVID‐19. After a COVID‐19 administration, increased blood viscosity
occurs and might lead to myocarditis.
The patient with previous COVID‐19 might have more risk to get a problem of COVID‐19 vaccine‐induced hyperviscosity.
In an area with high prevalence of disease, a child with previous silent COVID‐19 is possible and the risk has to be monitored.