Platelet Dropping, Bleeding and the Requirement of New Round Treatment After Inactivated COVID-19 Vaccination in the ITP-Associated Patients in China: A Population-Based Retrospective Study

The occurrence of immune thrombocytopenia (ITP) has been reported in the healthy population receiving COVID-19 mRNA and adenovirus vaccines, but not in the inactivated ones. Significant drops in platelet counts and ITP relapses have also been observed in ITP patients receiving COVID-19 mRNA vaccines. However, the impact of the inactivated COVID-19 vaccine on ITP patients and even those cured ones remains unclear. The present study aims to investigate the impact of COVID-19 inactivated vaccines on these individuals with particular emphasis on platelet dropping events (PDE), bleeding, and the requirement of new round treatment. One hundred and eighteen ITP-associated patients (ITPAPs), including 27 cured (CITPPs) and 91 uncured (ITPPs), who received inactivated COVID-19 vaccination were retrospectively studied according to an internet-based questionnaire. After vaccination (AV) (within 1 month), ITPAPs experiencing PDE (31.36%), new bleeding events (22.88%), and the requirement of a new round treatment (22.03%) were reported. Time since diagnosis (TSD) of ITPAPs was negatively correlated with PDE and requirement of a new round treatment AV, with 1-year TSD. Medication during vaccination may help to reduce new bleeding events AV. These results together suggest that standard treatment for ITP is important for the stability of the immune system that is waved by the vaccine. However, in CITPPs, >5-year time since cured (TSC) had a higher proportion of PDE than <5-year ones. Both TSD and TSC are the risk factors for the three adverse events AV. In conclusion, we show here that the COVID-19 inactivated vaccine causes PDE in both ITPPs and CITPPs, which may, in turn, cause new bleeding events and the requirement of a new round treatment for the ITP recrudescence. More attention should be paid to ITPAPs and ITPPs with 5-year TSC.Funding Information: This research was supported by the National Natural Science Foundation of China (grant number 31870001) to X.Y.Z., the National Natural Science Foundation of China (grant number 81770116) to M.Y. and Science, Technology and Innovation Committee of Shenzhen, China (grant number JCYJ20190809180213349) to M.Y..Declaration of Interests: The authors have declared that no competing interests exist.Ethics Approval Statement: The study was approved by the Ethics Committee of the Seventh Affiliated Hospital, Sun Yat-sen University. No informed consent of patients was required.