High incidence of asymptomatic SARS-CoV-2 infection, Chongqing, China

  1. Yang Tao
  2. Panke Cheng
  3. Wen Chen
  4. Peng Wan
  5. Yaokai Chen
  6. Guodan Yuan
  7. Junjie Chen
  8. Da Huo
  9. Ge Guan
  10. Dayu Sun
  11. Ju Tan
  12. Guanyuan Yang
  13. Wen Zeng
  14. Chuhong Zhu

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Abstract

Background

SARS-CoV-2 has been a global pandemic, but the emergence of asymptomatic patients has caused difficulties in the prevention of the epidemic. Therefore, it is significant to understand the epidemiological characteristics of asymptomatic patients with SARS-CoV-2 infection.

Methods

In this single-center, retrospective and observational study, we collected data from 167 patients with SARS-CoV-2 infection treated in Chongqing Public Health Medical Center (Chongqing, China) from January to March 2020. The epidemiological characteristics and variable of these patients were collected and analyzed.

Findings

82.04% of the SARS-CoV-2 infected patients had a travel history in Wuhan or a history of contact with returnees from Wuhan, showing typical characteristics of imported cases, and the proportion of severe Covid-19 patients was 13.2%, of which 59% were imported from Wuhan. For the patients who was returnees from Wuhan, 18.1% was asymptomatic patients. In different infection periods, compared with the proportion after 1/31/2020, the proportion of asymptomatic patient among SARS-CoV-2 infected patient was higher(19% VS 1.5%). In different age groups, the proportion of asymptomatic patient was the highest(28.6%) in children group under 14, next in elder group over 70 (27.3%). Compared with mild and common Covid-19 patients, the mean latency of asymptomatic was longer (11.25 days VS 8.86 days), but the hospital length of stay was shorter (14.3 days VS 16.96 days).

Conclusion

The SARS-CoV-2 prevention needs to focus on the screening of asymptomatic patients in the community with a history of contact with the imported population, especially for children and the elderly population.

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  1. ScreenIT

    SciScore for 10.1101/2020.03.16.20037259: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: This study was approved by the Ethics Committee of Chongqing Public Health Medical Treatment Center (NO.2020-018-01-KY), informed consent was allowed to be waived.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical analysis in this study were conducted with SPSS 25.0.
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Limitations of this study: (1) Because some SARS-CoV-2 infected patients have been discharged from hospitals, and the early epidemic situation is severe, medical workers are devoted to fighting the epidemic, resulting in the loss of some patients’ files. (2) 167 Case data we used were from the Chongqing Public Health Medical Center, and the number of asymptomatic infections is 20, which is relatively small. More case data of asymptomatic patients are needed to confirm our results. (3) Due to the huge workload of medical workers, patients with pneumonia infected by virus complex bacteria are not distinguished. (4) Our data is artificially calculated and not automatically generated by the system, so it has a certain degree of subjectivity.

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2020.03.16.20037259v1 on medRxiv