Acquired immune thrombotic thrombocytopenic purpura develops after vaccination with CoronaVac

Researchers from the Second Affiliated Hospital of Nanjing Medical University, et al. have published a case report entitled "Acquired immune thrombotic thrombocytopenic purpura (TTP) associated with inactivated COVID-19 vaccine CoronaVac". This report was published in Frontiers of Medicine, Volume 18, Issue 4, 2024.

Acquired immune thrombotic thrombocytopenic purpura (TTP) is a rare but life-threatening bleeding disorder. Previous studies have reported cases of TTP following administration of mRNA- or adenoviral vector-based COVID-19 vaccines. However, whether inactivated COVID-19 vaccines (such as CoronaVac) could cause TTP and whether the symptoms of TTP cases induced by inactivated vaccines are different from those of previously reported cases remain unclear. The researchers reported two cases of TTP that developed after vaccination with CoronaVac. Both patients developed TTP after receiving the second dose of CoronaVac, with no abnormalities observed after the first dose. They presented with symptoms including fever, neurological abnormalities, renal dysfunction, thrombocytopenia, and hemolysis. Both patients achieved complete remission through several sessions of plasma exchange and immunosuppressive therapy. In addition, the study analyzed the incidence of TTP in Nanjing area from 2019 to 2022. The number of newly diagnosed TTP cases during this period was 11, 6, 16, and 17 respectively. The incidence of TTP decreased in 2020 and then increased in 2021-2022, which is presumably related to the administration of COVID-19 vaccines.

This study is the first report on TTP associated with inactivated COVID-19 vaccines such as CoronaVac. The rarity and delayed onset of TTP may be attributed to the relatively milder immune response induced by inactivated vaccines. Timely plasma exchange is a vital treatment for such TTP cases.