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. 2025 Jun 30:18:3219-3229.
doi: 10.2147/IDR.S521808. eCollection 2025.

Retrospective Analysis of Factors Associated with a Prolonged Nucleic Acid Conversion Time in Patients with COVID-19 at Fangcang Shelter Hospital

Yang Li #  1 , Yang Wei #  2 , Yu Wang  1 , Qiuxia Chen  1   3 , Xianhua Hou  1   3
Affiliations

Retrospective Analysis of Factors Associated with a Prolonged Nucleic Acid Conversion Time in Patients with COVID-19 at Fangcang Shelter Hospital

Yang Li et al. Infect Drug Resist. .

Abstract

Objective: The aim of this study was to explore the related factors for prolonged nucleic acid conversion time (NCT) in patients with SARS-CoV-2 Omicron variant, so as to help to prevent and control the epidemic.

Methods: This study retrospectively included 307 patients diagnosed with mild to moderate COVID-19 who were hospitalized in Shanghai International Exhibition Fangcang Shelter Hospital. Nucleic acid amplification detection method was used to detect 2019-nCoV nucleic acid in nasopharyngeal swab samples. Binary logistic regression models were developed to identify independent risk factors associated with the time to nucleic acid conversion, utilizing the Kaplan-Meier test for survival analysis.

Results: In total, 307 patients were included in the study, with the median of NCT was 8 (6, 10) days, ranging 2 to 24 days, by which patients were divided into early NCT (<8 days) and late NCT (≥8 days). There was no difference between early and late NCT groups in gender, nationality, diabetes, previous sleep disorder, dyssomnia and depression (P = 0.222, 0.552, 0.118, 0.501, 0.133 and 0.603, respectively). There was a statistically significant difference between the two groups at different age levels, hypertension, anxiety (P=0.002, 0.001, 0.034). In the late NCT group, compared to early NCT, more patients with symptoms(37.5 vs 19.0%; P < 0.001), only cough and expectoration (29.4 vs 14.3; P=0.001), myodynia (13.8 vs 4.1; P=0.014) and fatigue (13.8 vs 4.1; P=0.003) were statistically different. There was no significant difference in the presence or absence of vaccination and the number of vaccination between the two groups(P=0.340 and 0.435).

Conclusion: Our study showed that age, hypertension, and anxiety were independent risk factors associated with the NCT in patients with COVID-19. Potential risk factors should be taken into consideration for the strategy of quarantining infected patients.

Keywords: COVID-19; SARS-CoV-2Viral; negative conversion; risk factors.

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Conflict of interest statement

Qiuxia Chen and Xianhua Hou are co‐corresponding authors. We do not have any conflicts of interest associated with this publication. There was no significant financial support for this work that could have influenced its outcome.

Figures

Figure 1
Figure 1
The Kaplan Meier survival curves of 307 COVID-19 patients with SARS-CoV-2 RNA overall negative transformation.
Figure 2
Figure 2
Age was positively associated with NCT of viral RNA in patients (A) Hypertension was positively associated with NCT of viral RNA in patients (B) Anxiety was positively associated with NCT of viral RNA in patients(C) Fatigue had no significant difference in the duration of SARS-CoV-2 RNA negative conversion (D).
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