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Frontiers in Medical Science Research, 2023, 5(8); doi: 10.25236/FMSR.2023.050809.

Clinical characteristics of patients infected with SARS-Cov-2 omicron in Shanghai: focusing on mild type


Huahua Yi1,2,3, Ting Cheng1,2,3, Xiaoting Cai1,2,3, Jing Liu1,2,3, Changqiang Chen4, Jiayuan Lin5, Ling Chen1,2,3, Qijian Cheng1,2,3, Yong Li1,2,3

Corresponding Author:
Ling Chen

1Department of Pulmonary and Critical Care Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China

2Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, China

3Shanghai Key Laboratory of Emergency Prevention, Diagnosis and Treatment of Respiratory Infectious Diseases, Shanghai, China

4Department of clinical laboratory, Ruijin Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, China

5Department of Pharmacy, Ruijin Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, China


Omicron emerged in late February in Shanghai and rapidly reached an epidemic expansion. However, clinical features of patients infected with omicron and potential risk factors of extending viral clearance was not further described in China. We conducted an observational study among patients in hospital from March 19th to April 10th2022 in Shanghai. Clinical data including demography, vaccination and symptoms were all collected through electronic questionnaire. Viral loading was evaluated by real-time PCR for nasopharyngeal swabs every other day after admission. 267 patients were included in this study and all of them were classified as mild type. The rate of vaccination against SARS-Cov-2 was 86.52% (231/267), and 133 individuals received three doses. Compared to patients vaccinated, unvaccinated participants were older (p < 0.0001) and had a longer period of viral clearance [14.5 days (11-17.5) vs 11 days (9-13), p < 0.0001] as well as length of hospital stay [17 days (13-19) vs 13 days (9-17), p = 0.0021]. Among the 134 symptomatic patients, female (50.75% vs 35.34%, p = 0.0110) and cluster cases (49.25% vs 33.83%, p = 0.0106) took a greater proportion. Cough [106 (79.10%)], sputum production [66(49.25%)] and sore throat [40(29.85%)] ranked top three among symptoms. The time for viral clearance was significantly longer among symptomatic individuals than asymptomatic patients [11.5 days (10-14) vs 10.5 days (8-13), p = 0.0339], as well as the length of hospital stay [15 days (12-17) vs 9 days (9-17), p < 0.0001]. In multivariate logistics regression, it showed patients vaccinated against SARS-Cov-2 was lower risk of clearing viral over 11 days (OR, 0.41; 95%CI, 0.17-0.96), but individuals with comorbidity was at increased risk of clearing viral over 11 days (OR, 2.11; 95% CI, 0.17-0.96). Individuals infected with omicron present symptoms such as cough, sputum production or sore throat. Patients with comorbidity may have a longer period of viral clearance when infected with Omicron. Receiving vaccination against SARS-Cov-2 may be helpful.


omicron, symptom, vaccination, complication, viral clearance

Cite This Paper

Huahua Yi, Ting Cheng, Xiaoting Cai, Jing Liu, Changqiang Chen, Jiayuan Lin, Ling Chen, Qijian Cheng, Yong Li. Clinical characteristics of patients infected with SARS-Cov-2 omicron in Shanghai: focusing on mild type. Frontiers in Medical Science Research (2023) Vol. 5, Issue 8: 65-73. https://doi.org/10.25236/FMSR.2023.050809.


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