OC 33.3 - Absence of Hypercoagulability after nCoV-19 Vaccination: an observational longitudinal study

Monday, July 11, 2022

11:15 AM – 11:30 AM

Location: ExCel Center, ICC Capital Suite Room 7&12

Presentation Format: In-Person

Presenting Author(s)

Chiara Simion, MD

Resident
University of Padova
Padova, Veneto, Italy

Co-Author(s)

EC

Elena Campello

Assistant Professor
Department of Medicine, University of Padova, Italy
Padova, Veneto, Italy
CB

Cristiana Bulato

PhD
Department of Medicine, Thrombotic and Haemorrhagic Diseases Unit, University of Padua Medical School, Padua (Italy)
Padova, Veneto, Italy
LS

Luca Spiezia

Associate Professor
Department of Medicine, University of Padova, Italy
Padova, Veneto, Italy
DT

Daniela Tormene

MD, PhD
University of Padova
Padova, Veneto, Italy
CR

Claudia Radu

Assistant Professor
Unviersity of Padova
Padova, Veneto, Italy
SG

Sabrina Gavasso

Laboratory technician
Unviersity of Padova
Padova, Veneto, Italy
NP

Nicola Perin

Resident in internal MEedicine
Department of Medicine, University of Padova, Italy
Padova, Veneto, Italy
MS

Marta Sartori

Fellow
Padova University Hospital, Padova, Italy
Padova, Veneto, Italy
Paolo Simioni, MD, PhD

Full Professor
Department of Medicine, Thrombotic and Haemorrhagic Diseases Unit, University of Padua Medical School, Padua (Italy)
Padua, Veneto, Italy

Background: A large number of daily requests to exclude possible prothrombotic risk factors for COVID-19 vaccines were received.

Aims: Our aim was to longitudinally evaluate coagulation profiles in a series of healthy subjects who received COVID-19 vaccination and assess hypercoagulability thereafter.

Methods: Volunteers awaiting a first or second dose of either the ChAdOx1 or BNT162b2 vaccine were enrolled. Venous samples were obtained at baseline (before the vaccine) and longitudinally 3±2 days (T1) and 10±2 days after the vaccine (T2). Global coagulation monitoring was assessed via platelet count, whole blood thromboelastometry and impedance aggregometry, plasma thrombin generation and anti-PF4/heparin IgG antibodies. Informed consent was obtained and the study was approved by the local medical ethics committee.

Results: One hundred and twenty-two subjects were enrolled (61 [50%] ChAdOx1 and 61 BNT162b2). The ChAdOx1 cohort showed a slight but transient increase in thrombin generation (mainly endogenous thrombin potential [ETP] with thrombomodulin and ETP ratio) at T1, which promptly decreased at T2. In addition, the second dose of either vaccine was associated with increased thrombin peak, ETP with thrombomodulin and ETP ratio. At baseline, 3.2% of the ChAdOx1 cohort and 1.6% BNT162b2 cohort were positive for PF4/heparin antibodies with a stable titre through T1 and T2 (Figure 1). No relevant differences were detected in platelet count and aggregation, or thromboelastometry parameters. No thrombotic or haemorrhagic events occurred.

Conclusion(s): We can confirm that no clinically meaningful hypercoagulability occurred after either vaccine, albeit keeping in mind that thrombin generation may increase in the first days after the second dose of either vaccine and after the first dose of the ChAdOx1 vaccine.