Vaccination Status Not Associated With Acute Thromboembolism Risk in COVID-19

Adults hospitalized with COVID-19 are at increased risk for acute thromboembolism, but vaccination status may not need to be considered in anticoagulation decisions.

Regardless of vaccination status, adults hospitalized for COVID-19 infection are at increased risk for acute thromboembolism, according to study results presented at IDWeek 2022, held from October 19 to 23, in Washington, DC.

Researchers conducted a retrospective cohort study between March 2020 and March 2022 to assess the effects of COVID-19 vaccination status on the incidence of acute thromboembolism among adults hospitalized with COVID-19 infection. All included patients were receiving standard-dose thromboprophylaxis, and none were admitted to an intensive care unit (ICU). The primary outcome was acute thromboembolism incidence, and multiple logistic regression was used to identity associated risk factors.

A total of 1428 patients were included in the analysis, of whom 185 (13%) were vaccinated and 1243 (87%) were unvaccinated against COVID-19 infection. Of the vaccinated and unvaccinated patients, the mean age was 68.1 and 61.2 years, 53.5% and 53.5% were men, and 10.3% and 9.6% were Black, respectively. Significant differences were noted between the vaccinated vs unvaccinated groups in regard to comorbidities. These included the percentage of patients with diabetes (45.4% vs 36.0%; P =.014), heart failure (24.3% vs 7.4%; P <.0001), atrial fibrillation (16.2% vs 7.6%; P <.0001), cancer (18.4% vs 8.0%; P <.0001), chronic kidney disease (29.7% vs 16.6%; P <.0001), and immunodeficiency (14.6% vs 7.6%; P =.001).

There was an increased incidence of acute thromboembolism observed among vaccinated vs unvaccinated patients (7.0% vs 3.9%). However, after performing multiple logistic regression, this finding was not statistically significant (adjusted odds ratio [aOR], 1.35; 95% CI, 0.67-2.58; P =.38).

Further analysis between vaccinated vs unvaccinated patients showed the risk for acute thromboembolism was significantly associated with older age (68 vs 61 years; OR, 1.03; 95% CI, 1.01-1.05; P =.01) and heart failure (24% vs 7%; OR, 2.84; 95% CI, 1.35-6.00; P =.006).

In regard to the rate of mortality, no significant differences were noted between vaccinated vs unvaccinated patients (3.8% vs 4.8%; OR, 0.79; 95% CI, 0.35-1.69; P =.56).

Based on these findings, “Decisions to anticoagulate non-ICU patients hospitalized with acute COVID-19 infections may not need to consider COVID[-19] vaccination status in as part of medical decision making,” the researchers concluded.

Disclosures: Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.


McKinell J, Pham F, Yarashenka V, et al. Acute thromboembolism in non-ICU hospitalized patients with COVID-19 infection: Examining the impact of prior COVID vaccination. Presented at: IDWeek 2022; October 19-23; Washington, DC. Poster 239.