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Poster Networking

Venous Thromboembolism

PB0383 - SARS-CoV-2 vaccinations and risk of Venous Thrombosis – Case control study

Sunday, June 23, 2024
13:45 – 14:45 ICT
Room: Exhibition Hall

    Co-Author(s)

  • Wv

    Willian J. van Dijk

    PhD student
    Leiden University Medical Center
    Vlaardingen, Zuid-Holland, Netherlands

    • Co-Author(s)

  • AK

    Agnes Kant

    Director
    Netherlands Pharmacovigilance Centre Lareb
    Doesburg, Gelderland, Netherlands

    • Presenting Author(s)

  • FR

    Frits R Rosendaal

    Professor at Leiden University Medical Center and Chairman of the Clinical Epidemiology Department
    Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
    Leiden, Zuid-Holland, Netherlands

    • Co-Author(s)

  • Astrid van Hylckama Vlieg

    Associate professor
    Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
    Leiden, Zuid-Holland, Netherlands

Background: Conflicting results have been reported regarding the magnitude of the risk of venous thromboembolism (VTE) after SARS-CoV-2 vaccines.

Aims: To determine the risk of VTE after SARS-CoV-2 vaccination and to determine whether there are subgroups of individuals who are particularly at increased risk of VTE after vaccination.

Methods: Patients who had a first VTE in 2021 were selected from ten Dutch hospitals. Controls were included from a cohort of random selected Dutch citizens, without a thrombotic event in 2021. Participants were over 18 years old, able to understand Dutch or English, and were legally competent. Informed consent was obtained from all participants. The study was approved by local medical ethics committee and is funded by the Dutch Ministry of Health.
Details about history of VTE, vaccination status, and other risk factors for VTE were collected via a questionnaire and using data from Statistics Netherlands. We calculated odds ratios (OR; adjusted for age, sex, and week number of the index date) to study the association between VTE and type of SARS-CoV-2 vaccination in the 28 days before index date. Furthermore, we performed subgroup analysis to identify potential high risk groups for developing VTE after SARS-CoV-2 vaccination.

Results: In total, 1255 cases with a first VTE and 5332 controls were eligible for analysis. Overall, BNT162b2 was not associated with the risk of VTE, while mRNA-1273, AZD1222, and Ad26.26.COV2.S vaccines were (mildly) associated with the risk of VTE. Differences in the risk of VTE between type of vaccines were more pronounced in young and female participants, and in participants without other VTE risk factors (see table 1).

Conclusion(s): VTE risks varied between SARS-CoV-2 vaccine type and patients. More detailed analyses will be available at the conference. These results are not only important for SARS-CoV-2 vaccination planning, but also for future vaccination campaigns.