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

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 thrombinantithrombin (TAT), kallikreinC1-esterase-inhibitor (PKaC1Inh), factor(F)IXaAT, FXaAT, FXIaAT, FXIaalpha-1-antitrypsin (α1AT), FXIaC1inh, and FVIIaAT. Plasma concentrations of interleukin (IL)-6 and IL-18 were quantified via ELISA. Analyses were performed using Wilcoxon signed-rank test. RESULTS: Levels of FVIIaAT 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 TAT, PKaC1Inh, FIXaAT, FXaAT, FXIaAT, FXIaα1AT, FXIaC1inh, 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.