COVID-19 Vaccine and Cancer Patients: New Findings from Viterbo

Strategic Insights -

Researchers at the Department of Oncology and Hematology have published new findings on the relationship between COVID-19 mRNA-based vaccines and the risk of thromboembolic events in cancer patients undergoing active treatment. The study, which analyzed data from November 2021 to October 2022, found that cancer patients have no increased risk of developing venous thromboembolism (VTE) after receiving the third dose of the SARS-CoV-2 mRNA-BNT162b2 vaccine, regardless of the type of active therapy they were receiving. However, the study did find that a specific pattern of lymphocyte response appears to increase thromboembolic risk, suggesting that immune dysregulation may be a causal factor. These findings emphasize the need for additional monitoring after periodic COVID-19 vaccination in cancer patients.

Key Takeaways:

  • The study found that 31 venous thromboembolic events occurred in the general population, with an overall incidence rate of 7.2% (95% CI 5.0-10.1).
  • The median time to VTE development after booster immunization was 99 (95% CI 85-112) days.
  • Patients receiving targeted therapies (11.3% [95% CI 6.0-18.9]) or immune checkpoint inhibitors (16.2% [95% CI 6.2-32.0]) had a significantly higher incidence of VTE than the reference cohort (3.4% [95% CI 0.9-8.5]).
  • Univariate analysis of immune responses showed that only dynamic changes pertaining to NK cell distributions correlated significantly with VTE occurrence.
  • Multivariate regression analysis confirmed that a high-level NK cell response (OR 6.10 [9% CI 2.16-17.21]) and a history of thromboembolic events (OR 9.81 [3.99-24.13]) were associated with an increased risk of VTE.
  • The study concluded that cancer patients have no increased risk of developing VTE after the third dose of the SARS-CoV-2 mRNA-BNT162b2 vaccine, regardless of the type of active therapy they were receiving.
  • The specific pattern of lymphocyte response appears to increase thromboembolic risk, suggesting that immune dysregulation may be a causal factor.

Statistics:

  • The overall incidence rate of VTE was 7.2% (95% CI 5.0-10.1) in the general population.
  • The median time to VTE development after booster immunization was 99 (95% CI 85-112) days.
  • Patients receiving targeted therapies had an incidence rate of 11.3% (95% CI 6.0-18.9) of VTE.
  • Patients receiving immune checkpoint inhibitors had an incidence rate of 16.2% (95% CI 6.2-32.0) of VTE.
  • The reference cohort had an incidence rate of 3.4% (95% CI 0.9-8.5) of VTE.

Sources:

  • Venous Thromboembolic Risk Does Not Increase After a Third Dose of SARS-CoV-2 mRNA-BNT162b2 Vaccine in Cancer Patients Receiving Active Systemic Therapies: Updated Results from the Vax-On-Third-Profile Study. Vaccines, 2025, 13(4):392. (Vaccines - http://www.mdpi.com/journal/vaccines). The publisher for Vaccines is MDPI AG.