Clinical Characteristics of Omicron SARS-CoV-2 Variant Infection After Non-mRNA-Based Vaccination in China

Qing-Lei Zeng; Yuan-Jun Lv; Xiao-Jing Liu; Zhi-Yong Jiang; Shuo Huang; Wei-Zhe Li; Zu-Jiang Yu

doi:10.3389/fmicb.2022.901826

Clinical Characteristics of Omicron SARS-CoV-2 Variant Infection After Non-mRNA-Based Vaccination in China

Front Microbiol. 2022 Jun 30:13:901826. doi: 10.3389/fmicb.2022.901826. eCollection 2022.

Authors

Qing-Lei Zeng¹, Yuan-Jun Lv², Xiao-Jing Liu³, Zhi-Yong Jiang⁴, Shuo Huang¹, Wei-Zhe Li¹, Zu-Jiang Yu¹

Affiliations

¹ Department of Infectious Diseases, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
² Department of Respiratory Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
³ Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
⁴ Department of Internal Medicine, The Fifth People's Hospital of Anyang City, Anyang, China.

Abstract

Introduction: To date, little is known about the real-world protective role of Chinese inactivated and recombinant coronavirus disease 2019 (COVID-19) vaccines under the background of the long-term "Dynamic Zero COVID-19 Case" (i.e., no infection source) in China, especially when facing the widespread Omicron severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant infection.

Methods: In this prospective, single-center cohort study, the clinical characteristics of post-vaccination Omicron SARS-CoV-2 variant infection were investigated in the initial largest outbreak of Omicron SARS-CoV-2 variant infection that occurred between the 8 January, 2022 and 29 January, 2022 in Anyang City, Henan Province, China. The primary endpoints were the rates of severe and critical diseases or death. The secondary endpoints were the SARS-CoV-2 shedding duration and length of hospitalization.

Results: A total of 380 post-vaccination patients infected with the Omicron SARS-CoV-2 variant were enrolled. The median age was 18 (interquartile range [IQR] 17-35) years, 219 (57.6%) cases were female, and 247 (65.0%) cases were students. Before confirmation of Omicron SARS-CoV-2 variant infection, patients had 3 (IQR 2-4) days of dry cough (40.3%), nasal congestion (26.3%), and sore throat (26.3%). On admission, 294 (77.4%) cases had normal chest computerized tomography (CT) imaging. Additionally, only 5 (1.3%), 30 (7.9%), 4 (4/342, 1.2%), and 7 (7/379, 0.2%) patients had lymphocyte counts <800 per mm³, C-reactive protein levels >10 mg/L, lactate dehydrogenase levels ≥250 U/L, and D-dimer levels ≥0.5 mg/L on admission, respectively. During hospitalization, 308 (81.1%) and 72 (18.9%) were identified as mild and moderate cases, respectively, and no one progressed to severe and critical types, with a SARS-CoV-2 shedding period and length of hospital stay of 17 (IQR 12-22) and 19 (IQR 15-24) days, respectively.

Conclusion: The current study found that approximately 80% of individuals infected with the Omicron SARS-CoV-2 variant were mild, approximately 20% of patients were moderate, and no severe, critical, or fatal cases were identified in a prospective cohort including 380 participants vaccinated with non-mRNA-based vaccines.

Discussion: This study supports the consideration of policy adjustments and changes to prevent and control the Omicron-predominant COVID-19 in China and other regions with high SARS-CoV-2 vaccination rates.

Keywords: China; coronavirus disease 2019; omicron variant; severe acute respiratory syndrome coronavirus 2; vaccination; viral shedding.