CT Imaging Study Finds Vaccination Reduces Risk of COVID-19 Associated Pulmonary Embolism

The study by researchers at the University of Utah examined the prevalence of PE in COVID-infected patients in a single ER over dominant periods of the ancestral, Delta, and Omicron variants of COVID-19. Their findings showed a difference in the incidence of PE in ED patients infected with the ancestral COVID-19 variants and those infected with the Delta and Omicron COVID-19 variants. Though the findings do not reach statistical significance, they suggest that patients infected with the Delta or Omicron COVID-19 variants may have a lower incidence of pulmonary embolism. Additionally, the researchers also found that vaccination with at least two doses does significantly reduce the risk of COVID-19 associated PE.

For the study, the researchers collected demographic information, patient comorbidities and risk factors, vaccination status, and COVID-19 infection status from patient’s charts. They compared the incidence of PE in COVID positive patients between variant waves and performed subgroup analysis of vaccination effect. CTPA was ordered in 18.3% of COVID-19 positive patients during the ancestral variant period, 18.3% during the Delta period and 17.3% during the Omicron wave. PE was seen in 15.0% of the ancestral COVID-19 variant cohort, 10.6% in the Delta COVID cohort and 9.23% of the Omicron cohort, reflecting a 41% and 60% increased risk of PE with ancestral variants compared to Delta and Omicron periods, respectively. The study also found that unvaccinated patients had a 2.75-fold increased risk of COVID-associated PE during the Delta and Omicron periods as compared to vaccinated or recovered patients.

Based on these findings, the researchers concluded that vaccination reduces the risk of COVID-19 associated PE. Patients infected with the Delta and Omicron COVID-19 variants may have a lower incidence of pulmonary embolism, though a larger or multi-institution study is needed to prove definitively.

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