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Res Pract Thromb Haemost
. 2026 Mar 23;10(3):103415.
doi: 10.1016/j.rpth.2026.103415. eCollection 2026 Mar.
A comprehensive assessment of the impact of COVID variant and vaccination on venous thromboembolism and mortality
Samuel P Soff 1 2 , Richard Moffitt 3 4 , Anjali Sharathkumar 5 , Margaret A Hall 4 , Rachel Wong 2 6 , Yun J Yoo 4 , Gerald A Soff 7 ; National Clinical Cohort Collaborative COVID-19 Enclave
Affiliations
Background: COVID-19 is associated with increased mortality and morbidity. The mortality and adverse outcomes of current era COVID-19 variants have not been comprehensively studied.
Objectives: To evaluate the association between COVID-19 variants and vaccination status on venous thromboembolism (VTE) and mortality rates, especially among recent strains, compared to a control group with acute respiratory infection (ARI).
Methods: A retrospective cohort study was conducted using the National Clinical Cohort Collaborative database. Inclusion criteria were adult patients with COVID-19 or ARI between March 1, 2020 and November 1, 2024. Cohorts were balanced on demographics, prior healthcare visits, prior anticoagulation/antiplatelet use, COVID-19 vaccination and comorbidities. Primary outcomes were 30-day VTE and mortality using multivariable regression analysis. Kaplan-Meier survival curves were used to determine the duration of post-infectious VTE and mortality risk.
Results: A total of 756,217 patients with COVID-19 and 678,747 with ARI were included. Patients with COVID-19 had an increased risk of VTE (odds ratio [OR]: 1.45) and mortality (OR: 1.80) compared to the ARI cohort. However, risk was attenuated later in the pandemic, with similar risk between patients with COVID-19 and ARI in the Contemporary Omicron period (May 2022-Nov 2024), especially among vaccinated individuals. Vaccination was associated with a reduced odds of VTE (OR: 0.41) and mortality (OR: 0.41). The post-COVID elevated VTE and mortality risk plateaued after 8 weeks.
Conclusion: COVID-19 was associated with increased risk of 30-day VTE and mortality compared to ARI, but was no longer significantly different during the contemporary period (2022-2024) of the pandemic. COVID-19 vaccination was associated with reduced VTE events and mortality.
Keywords: COVID-19; vaccine; venous thrombosis.
. 2026 Mar 23;10(3):103415.
doi: 10.1016/j.rpth.2026.103415. eCollection 2026 Mar.
A comprehensive assessment of the impact of COVID variant and vaccination on venous thromboembolism and mortality
Samuel P Soff 1 2 , Richard Moffitt 3 4 , Anjali Sharathkumar 5 , Margaret A Hall 4 , Rachel Wong 2 6 , Yun J Yoo 4 , Gerald A Soff 7 ; National Clinical Cohort Collaborative COVID-19 Enclave
Affiliations
- PMID: 42079673
- PMCID: PMC13129423
- DOI: 10.1016/j.rpth.2026.103415
Background: COVID-19 is associated with increased mortality and morbidity. The mortality and adverse outcomes of current era COVID-19 variants have not been comprehensively studied.
Objectives: To evaluate the association between COVID-19 variants and vaccination status on venous thromboembolism (VTE) and mortality rates, especially among recent strains, compared to a control group with acute respiratory infection (ARI).
Methods: A retrospective cohort study was conducted using the National Clinical Cohort Collaborative database. Inclusion criteria were adult patients with COVID-19 or ARI between March 1, 2020 and November 1, 2024. Cohorts were balanced on demographics, prior healthcare visits, prior anticoagulation/antiplatelet use, COVID-19 vaccination and comorbidities. Primary outcomes were 30-day VTE and mortality using multivariable regression analysis. Kaplan-Meier survival curves were used to determine the duration of post-infectious VTE and mortality risk.
Results: A total of 756,217 patients with COVID-19 and 678,747 with ARI were included. Patients with COVID-19 had an increased risk of VTE (odds ratio [OR]: 1.45) and mortality (OR: 1.80) compared to the ARI cohort. However, risk was attenuated later in the pandemic, with similar risk between patients with COVID-19 and ARI in the Contemporary Omicron period (May 2022-Nov 2024), especially among vaccinated individuals. Vaccination was associated with a reduced odds of VTE (OR: 0.41) and mortality (OR: 0.41). The post-COVID elevated VTE and mortality risk plateaued after 8 weeks.
Conclusion: COVID-19 was associated with increased risk of 30-day VTE and mortality compared to ARI, but was no longer significantly different during the contemporary period (2022-2024) of the pandemic. COVID-19 vaccination was associated with reduced VTE events and mortality.
Keywords: COVID-19; vaccine; venous thrombosis.