Concurrent hypereosinophilic syndrome and deep vein thrombosis after Pfizer-BioNTech COVID-19 vaccination: A case report.

Herein, we report a case of eosinophilia syndrome and deep vein thrombosis presenting concurrently after the administration of the BNT162b2 mRNA-based coronavirus disease 2019 (COVID-19) vaccine. It is extremely rare to have both hypereosinophilic syndrome and deep vein thrombosis simultaneously. Both are serious diseases and should be treated with caution.