ChAdOx1 vaccination, blood coagulation, and inflammation: No effect on coagulation but increased interleukin‐6

Abstract

Abstract Background Vaccination is the leading approach in combatting the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) pandemic. ChAdOx1 nCoV‐19 vaccination (ChAdOx1) has been linked to a higher frequency of rare thrombosis and thromboembolism. This study aimed to explore markers related to the blood coagulation system activation and inflammation, before and after ChAdOx1 vaccination. Patients and Methods An observational cohort study including 40 health care workers. Whole blood samples were collected before, and either 1 or 2 days after vaccination. Activated coagulation factors in complex with their natural inhibitors were determined by custom ELISAs, including thrombin:antithrombin (T:AT), kallikrein:C1‐esterase‐inhibitor (PKa:C1Inh), factor(F)IXa:AT, FXa:AT, FXIaAT, FXIa:alpha‐1‐antitrypsin (α1AT), FXIa:C1inh, and FVIIa:AT. Plasma concentrations of interleukin (IL)‐6 and IL‐18 were quantified via ELISA. Analyses were performed using Wilcoxon signed‐rank test. Results Levels of FVIIa:AT decreased with a median (IQR) of 707 (549–1028) pg/ml versus 598 (471–996) pg/ml, p = 0.01; and levels of IL‐6 increased, 4.0 (1.9–6.8) pg/ml versus 6.9 (3.6–12.2) pg/ml, p = 0.02, after vaccination. No changes were observed in T:AT, PKa:C1Inh, FIXa:AT, FXa:AT, FXIaAT, FXIa:α1AT, FXIa:C1inh, and IL‐18. Conclusion ChAdOx1 leads to an inflammatory response with increased levels of IL‐6. We did not observe activation of the blood coagulation system 1–2 days following vaccination.

Keywords

• blood coagulation
• COVID‐19
• COVID‐19 vaccines
• SARS‐CoV‐2
• thrombosis
• vaccination