Oxford-AstraZeneca Coronavirus Disease-2019 Vaccine-Induced Immune Thrombocytopenia on Day Two.

Patients with a history of thrombocytopenia can develop vaccine-induced thrombocytopenia earlier than the expected onset. Close monitoring, through regular complete blood counts, is highly recommended for patients with previous thrombocytopenia because the immune modulation process of the vaccine can worsen preexisting thrombocytopenia.