Is the Omicron variant truly less virulent in solid organ transplant recipients?

Solid organ transplant (SOT) recipients are at high risk for severe disease with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Emerging variants of concern have disproportionately affected this population. Data on severity and outcomes with the Omicron variant in SOT recipients are limited. Thus we conducted this single-center, retrospective cohort study of SOT recipients diagnosed with SARS-CoV-2 infection from December 18, 2021 to January 18, 2022, when prevalence of the Omicron variant was more than 80%-95% in the community. Univariate and multivariate logistic regression analysis was performed to identify risk factors for hospital admission. We identified 166 SOT patients: 112 (67.5%) kidney, 22 (13.3%) liver, 10 (6.0%) lung, seven (4.2%) heart, and 15 (9.0%) combined transplants. SARS-CoV-2 vaccine series was completed in 59 (35.5%) recipients. Ninety-nine (59.6%) and 13 (7.8%) recipients received casirivimab/imdevimab and sotrovimab, respectively. Fifty-three (32%) recipients required hospital admission, of which 19 (35.8%) required intensive care unit level of care. Median follow-up was 50 (interquartile range, 25-59) days, with mortality reported in six (3.6%) patients. Risk factors identified for hospital admission were African American race (p < .001, odds ratio [OR] 4.00, 95% confidence interval [CI] 1.84-8.70), history of coronary artery disease (p = .031, OR 3.50, 95% CI 1.12-10.87), and maintenance immunosuppression with corticosteroids (p = .048, OR 2.00, 95% CI 1.01-4.00). In conclusion, contrary to that in the general population, we found a higher hospital admission rate in SOT recipients with omicron variant infection. Further studies to investigate the efficacy of newer treatments are necessary, even as outcomes continue to improve.