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

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

Qing-Lei Zeng  1 , Yuan-Jun Lv  2 , Xiao-Jing Liu  3 , Zhi-Yong Jiang  4 , Shuo Huang  1 , Wei-Zhe Li  1 , Zu-Jiang Yu  1
Affiliations

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

Qing-Lei Zeng et al. Front Microbiol. .

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.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Chest computerized tomography images of patients with Omicron SARS-CoV-2 variant infection after inactivated and recombinant vaccinations in China. (A) Normal chest computerized tomography images. (B) Ground-glass opacity in left lung. (C) Mildly bilateral ground-glass opacity and patchy shadows.
Figure 2
Figure 2
Clinical classification of Omicron SARS-CoV-2 variant infection after inactivated and recombinant vaccinations in China.
See this image and copyright information in PMC

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