BNT162b2 mRNA SARS-CoV- 2 vaccination does not cause upregulation of endothelial activation markers or hypercoagulability: A prospective, single-arm, longitudinal study

ABSTRACT

Background: Reports of thrombosis post COVID-19 mRNA vaccination have sparked concerns about safety. Aim(s) We prospectively evaluated blood samples of 18 participants who had received 2 doses of the BNT162b2 mRNA vaccine to determine if vaccination results in endothelial activation or hypercoagulability. Method(s) 18 participants who received the BNT162b2 vaccine were enrolled. Participants completed a questionnaire on their cardiovascular and thrombotic risk factors. Blood samples were collected at three time points Pre-vaccination (day of vaccination), a median of 17 (IQR 16-18) days after the first dose and a median of 9 (IQR 7.5-14.5) days after the second dose of BNT162b2 vaccine. Endothelial markers included ICAM-1, VCAM-1 and P-selectin. Coagulation tests included PT and aPTT with clot waveform analysis, von Willebrand factor levels, Factor VIII and D-dimer levels. Statistical tests of association between endothelial and coagulation parameters were performed with repeated measures ANOVA and Mauchly's test of sphericity. Result(s) The median age of the participants was 35 years (IQR 31 -44), and 14 (78%) were female. 15 did not have any cardiovascular risk factors. There was a statistically significant increase in median ICAM levels post first (66.1ng/ml) and second dose of vaccination (69.5ng/ml)(p = 0.04), although this remained within the normal limit of ICAM levels. A statistically significant decrease in median PT (p = 0.005) and aPTT (p = 0.03) was observed post vaccination, with a corresponding statistically significant increase in aPTT clot waveform analysis (CWA) for maximum acceleration (max2)(p = 0.03) and maximum deceleration (max2)(p = 0.04) post first and second dose of vaccination. However, all evaluated endothelial and coagulation parameters remain within the reference ranges (Table 1). Conclusion(s) Our findings provide reassuring preliminary data that BNT162b2 vaccination does not result in endothelial activation or hypercoagulability. Mild variations in endothelial markers and coagulation parameters, though statistically significant, remain within the reference ranges and may be related to an inflammatory immune response to vaccination. (Table Presented).