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

L.H. Willems*, M. Nagy, H. Ten Cate, H.M.H. Spronk, L.M.C. Jacobs, J. Kranendonk, M. van Leeuwen, D. Meijer, S. Middeldorp, L.A. Groh, M.C. Warle

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


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:C1esterase-inhibitor (PKa:C1Inh), factor(F)IXa:AT, FXa:AT, FXIaAT, FXIa:alpha-1-antitrypsin (alpha 1AT), 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/mI, 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, FX1a:alpha 1AT, FXIa:C1inh, and IL-18.Conclusion: ChAdOx1 leads to an inflammatory response with increased levels of IL6. We did not observe activation of the blood coagulation system 1-2 days following vaccination.
Original languageEnglish
Article numbere12630
Number of pages5
JournalResearch and practice in thrombosis and haemostasis
Issue number8
Publication statusPublished - 1 Dec 2021


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


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