Clin Transplant Res.  2025 Mar;39(1):46-54. 10.4285/ctr.24.0045.

Predictors of moderate, severe, and critical COVID-19 infection in a largely vaccinated kidney transplant recipient cohort during the Omicron era: the importance of timely booster vaccinations and early presentation to care

• Gan CLS
• Chung SJ
• Ho QY
• Tan TT
• Tan BH
• Liew IT
• Tien CSY
• Thangaraju S
• Kee T

• KMID: 2566579
• DOI: http://doi.org/10.4285/ctr.24.0045

Abstract

Background
Kidney transplant recipients (KTRs) are at risk of coronavirus disease 2019 (COVID-19) complications and mortality. This study examined factors associated with moderate, severe, or critical COVID-19 infection among KTRs during the Omicron-predominant period.
Methods
This single-center retrospective study included KTRs aged ≥18 years diag-nosed with COVID-19 between January 1, 2022, and December 31, 2023. Mild infection was defined as symptomatic illness without lower respiratory tract infection (LRTI); moderate infection as LRTI without hypoxia; severe infection as oxygen saturation <94% on room air; and critical infection as respiratory failure, septic shock, or multiple organ dysfunction. We compared the characteristics of KTRs with asymptomatic or mild COVID-19 versus those with moderate to critical disease. Logistic regression analysis was performed to identify factors associated with moderate to critical illness.
Results
Most KTRs (94.4%) had received three or more vaccine doses. Of 603 episodes of COVID-19 infection during the study period, 554 (91.9%) were asymptomatic or mild, while 49 (8.1%) were moderate to critical. Multivariate analysis revealed that older age (adjusted odds ratio [aOR], 1.037; 95% confidence interval [CI], 1.006–1.069) and longer symptom duration before seeking care (aOR, 1.288; 95% CI, 1.155–1.436) were associated with higher odds of moderate to critical disease. Protective factors included receiving a vaccine booster within the past year (aOR, 0.414; 95% CI, 0.212–0.809) and higher glomerular filtration rate (aOR, 0.971; 95% CI, 0.956–0.986).
Conclusions
KTRs should seek care early if infected with COVID-19 and keep their COVID-19 vaccine boosters updated within 1 year of the last dose.

Keyword

COVID-19; SARS-CoV-2; Kidney transplantation; Omicron; Vaccination

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