ChAdOx1 nCoV-19 vaccine-associated thrombocytopenia: three cases of immune thrombocytopenia after 107 720 doses of ChAdOx1 vaccination in Thailand

Abstract

We reported three cases of immune thrombocytopenia (ITP) that developed within 6 weeks after ChAdOx1 nCoV-19 vaccination. Antiplatelet factor 4 antibodies were undetectable in all three cases. Therefore, vaccine-induced immune thrombotic thrombocytopenia was very unlikely. Other potential causes of thrombocytopenia were excluded. Their clinical presentations, severity of thrombocytopenia and outcomes were varied. Only one ITP case, an 80-yearold man, received ITP treatments and achieved complete response after 2 weeks of eltrombopag. An 84-year-old man had spontaneous complete remission, and a 55-year-old woman had partial platelet recovery without ITP treatments. Among 107 720 Thais administered the ChAdOx1 vaccine between 16 March and 10 May 2021, these three ITP cases resulted in an estimated risk of ITP of at least one per 36 000 doses, which was approximately similar to the risk of ITP after measles-mumps-rubella immunization. This raises the concern of an increased risk of ITP after ChAdOx1 vaccination. Blood Coagul Fibrinolysis

Thrombosis and thrombocytopenia in COVID-19 and after COVID-19 vaccination

“…The incidence was quite low, and 0.80 per million doses for both vaccines, which is not greater than the number of ITP cases expected [66] . The case number is even fewer, but cases of thrombocytopenia with negative anti-PF4 antibody after ChAdOx1 vaccination were reported [67] . Since the diagnostic accuracy of platelet-associated IgG is not high, those cases may be diagnosed as ITP without testing platelet-associated IgG.…”

COVID‐19‐induced immune thrombocytopenia management approach: A case report and literature review

“…22 In addition, a study from Thailand reported that the risk of ITP post ChAdOx1 nCoV-19 vaccine was similar to that of the MMR vaccine, at least 1 per 36,000 doses. 10 In our review there was 1 patient who received the Pfizer-BioNTech vaccine 1 day before the onset of ITP and the MMR vaccine 2 months prior to ITP onset. 11 As for mortality due to COVID-19-vaccine-induced ITP, one case series reported 2 fatalities resulting from intracranial hemorrhage caused by ITP, acute myocardial infarction, and pulmonary embolism.…”

“…1 Similarly, from 2021 to 2022, more than 37 studies were reported worldwide associating vaccination against SARS-CoV-2 virus with de novo ITP. [7][8][9][10][11][12][13][14][15][16] According to another systematic review, published in September 2020, on the incidence of ITP secondary to COVID-19 infection, the overall response of ITP to first-line therapy, which included corticosteroids and intravenous immunoglobulin (IVIG), was good, and mortality was only reported in 1 case, due to intracranial hemorrhage (even though severe bleeding was not a common finding among all other cases). 17 In this paper, we report the case of a 39-year-old male patient who developed severe refractory ITP 4-weeks after receiving his third (booster) dose of the COVID-19 vaccine (BNT162b2, Pfizer-BioNTech).…”

Severe case of refractory immune thrombocytopenic purpura requiring splenectomy after the COVID-19 vaccine

“…In particular, several cases of ITP have been reported after the BTN162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna) SARS-CoV-2 (COVID-19) vaccines 3. The estimated risk of ITP after an mRNA-based SARS-CoV-2 vaccine is approximately 1 per every 36 000 doses, which is similar to the incidence of ITP after the measles, mumps and rubella (MMR) vaccine 4. To date, however, all reported cases of ITP after an mRNA-based SARS-CoV-2 vaccine have responded to medical management.…”

“… 3 The estimated risk of ITP after an mRNA-based SARS-CoV-2 vaccine is approximately 1 per every 36 000 doses, which is similar to the incidence of ITP after the measles, mumps and rubella (MMR) vaccine. 4 To date, however, all reported cases of ITP after an mRNA-based SARS-CoV-2 vaccine have responded to medical management. Here, we present a case of severe, refractory ITP that failed to respond to several medical treatments over the course of 2 months and eventually required a splenectomy for the management of severe thrombocytopenia.…”