A Disproportionality Analysis for Association of Systemic Capillary Leak Syndrome with COVID-19 Vaccination Using the World Health Organization Pharmacovigilance Database

Systemic capillary leak syndrome (SCLS) is a rare and potentially life-threatening disorder characterized by reversible plasma extravasation and vascular collapse. This study aimed to investigate the association between different types of COVID-19 vaccine and SCLS in a real-world setting. We used individual case safety reports of SCLS after COVID-19 vaccination from the WHO pharmacovigilance database, VigiBase. A disproportionality analysis of ChAdOx1 nCoV-19 and mRNA-based vaccines was performed. The information component (IC) and reporting odds ratio (ROR) were calculated from the entire database and viral vaccines data subset. A positive 95% lower end of the IC (IC₀₂₅) value (>0) using Bayesian neural network analysis and lower end of the ROR 95% confidence interval (ROR₀₂₅) ≥1 were defined as the ADR signal detection threshold. A total of 101 (0.004%) events of SCLS were identified. A significant potential signal of disproportionality of SCLS was noted in ChAdOx1 nCoV-19 when applied as the denominator for entire database (IC₀₂₅ = 0.24, ROR₀₂₅ = 1.23) and all viral vaccines (IC₀₂₅ = 0.41, ROR₀₂₅ = 1.59). No significant potential signal was noted for two mRNA-based vaccines as denominators for the entire database (IC₀₂₅ = −0.49, ROR₀₂₅ = 0.71) and all viral vaccines (IC₀₂₅ = −0.32, ROR₀₂₅ = 0.77). Contrary to ChAdOx1 nCoV-1, no safety signal for developing SCLS was identified for mRNA-based vaccines.