Differential Characteristics of Patients for Hospitalized Severe COVID-19 Infected by the Omicron Variants and Wild Type of SARS-CoV-2 in China

Abstract

Background

As multiple mutations of SARS-Cov-2 exist, there are now many viral variants with regional differences in distribution. The clinical characteristics of patients hospitalized with the virus also vary significantly, with those of the Omicron variants being strikingly different from those of the earliest wild-type variant. However, comprehensive data on this subject is lacking. It is therefore crucial to explore these differences to develop better clinical strategies for the management of COVID-19.

Methods

A total of 554 confirmed COVID-19 cases in China were clinically classified as mild, moderate, severe, and critical according to their diagnoses and treatment plans. We compared the demographics and clinical characteristics of patients infected with the Omicron vs wild-type strains, between severe and non-severe cases. Bacterial co-infections with SARS-CoV-2 and correlation between inflammatory factors and T cells were analyzed.

Results

Compared to the wild-type cases, the severe Omicron cases were older (median age 48.36 vs 73.24), and had more upper-respiratory symptoms and comorbidities. Decreased leukocyte counts were less pronounced, although more instances of significantly decreased CD4+ and CD8+ T-cell counts, elevated infection-related biomarkers (eg procalcitonin and C-reactive protein), and abnormal coagulation factors (including increased D-dimer and fibrinogen levels) were detected in the severe Omicron cases. The mean length of hospital stay was significantly shorter in the severe Omicron cases. CD4+ and CD8+ T cell numbers were negatively correlated with neutrophil-to-lymphocyte ratios, as well as serum interleukin-6, procalcitonin, and C-reactive protein levels.

Conclusion

There were significant clinical differences between patients hospitalized with severe cases of Omicron- variant COVID-19 vs wild-type. The Omicron cases tended to be older and had more upper respiratory tract symptoms, comorbidities and bacterial co-infections. Elevated levels of inflammatory cytokines with T-cell depletion correlated with poor disease progression and prognosis. We hope these data provide a theoretical basis for future integrated prevention and control plans for COVID-19.

Keywords:

• COVID-19
• Omicron variants
• wild-typeSARS-CoV-2
• clinical characteristics
• T cell depletion

Abbreviations

SARS-CoV-2, Severe Acute Respiratory Syndrome Coronavirus 2; ACE2, angiotensin converting enzyme 2; RT-PCR, Reverse Transcription-Polymerase Chain Reaction; PCT, procalcitonin; CRP, C-reactive protein; ALT, Alanine aminotransferase; AST, Aspartate aminotransferase; Tbil, total bilirubin; BUN, blood urea nitrogen; Ccr, Creatinine Clearance Rate; IL-6, interleukin 6; CK, creatine kinase; CK-MB, isoenzyme of creatine kinase; LDH, lactate dehydrogenase; NLR, neutrophil to lymphocyte ratio; PT, Prothrombin time; APTT, activated partial thromboplastin time; SARS, Severe Acute Respiratory Syndrome; ICU, Intensive Care Unit; ARDS, acute respiratory distress syndrome.

Data Sharing Statement

All data reported in this study are available from the corresponding authors (Guang-He Fei and Ming-Feng Han) upon reasonable request, following institutional approval.

Ethics Approval

The study complied with the Declaration of Helsinki and was approved by the First Affiliated Hospital of Anhui Medical University Ethics Committee (No: 2022371).

Consent for Publication

All patients involved in this study gave written informed consent to participate, and the authors have reviewed and approved the final version of the manuscript.

Author Contributions

All authors made a significant contributions to the work reported, including the conception, study design, execution, acquisition of data, analysis and interpretation, in addition to participating in drafting, revising, or critically reviewing the article. All authors provided final approvals of the version to be submitted for publication, as well as agreed on the journal to which the article has been submitted, with full accountability for all aspects of the work.

Disclosure

The authors have no conflicts of interest to disclose for this work.

Additional information

Funding

This work was supported by a grant from the Key Technology Research and Development Program of Anhui Province (No. 2022e07020076).