Comparative Analysis of De Novo Immune Thrombocytopenia Following mRNA COVID-19 Vaccine Versus Non-mRNA Vaccines and COVID-19: A Global Database Analysis.

Introduction Autoimmune diseases have been linked to COVID-19 vaccines. An increasing number of cases have reported de novo immune thrombocytopenia (ITP) following mRNA COVID-19 vaccines. This study aims to investigate the incidence of de novo ITP following the mRNA COVID-19 vaccine in comparison to other non-mRNA vaccines and COVID-19. Methods Data were collected from the TriNetX global health research network, which covers over 117 million patients. Four different patient cohorts were included: those who received the mRNA COVID-19 vaccine (between 12/15/2020 - 5/1/2023), the influenza vaccine (between 01/01/2010 - 01/01/2020), tetanus, diphtheria, and pertussis/tetanus and diphtheria (Tdap/Td) vaccines (between 01/01/2010 - 01/01/2020), and those who had COVID-19 (between 01/01/2020 - 05/01/2023). A comparative analysis was conducted to examine the occurrence of de novo ITP within three weeks after receiving mRNA COVID-19 vaccine, non-mRNA vaccines, or upon diagnosis of COVID-19. Additionally, a comparative analysis was performed after 1:1 propensity score matching to balance baseline characteristics (age, sex, and race). Results The overall event rate was 0.07 per 10,000 for the mRNA COVID-19 vaccine, 0.25 per 10,000 for the influenza vaccine, and 0.28 per 10,000 for the Tdap/Td vaccines. Additionally, the incidence of de novo ITP following COVID-19 was 0.30 per 10,000. Those who received the influenza vaccine and Tdap/Td vaccines had higher rates of de novo ITP compared to the mRNA COVID-19 vaccine group, with a relative risk of 3.48 and 3.88, respectively. The occurrence of de novo ITP following COVID-19 was significantly higher compared to that following the mRNA COVID-19 vaccine, with a relative risk of 4.27. Post-propensity score matching analysis produced similar outcomes. Conclusions The findings of this study suggest that the incidence of de novo ITP is significantly lower following mRNA-based COVID-19 vaccines compared to non-mRNA vaccines and COVID-19.