Rapid asymptomatic transmission of COVID-19 during the incubation period demonstrating strong infectivity in a cluster of youngsters aged 16-23 years outside Wuhan and characteristics of young patients with COVID-19: A prospective contact-tracing study

  • Author Footnotes
    1 These authors contributed equally to this article.
    Lei Huang
    Correspondence
    Corresponding authors.
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    1 These authors contributed equally to this article.
    Affiliations
    Department of General Surgery, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China
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    Xiuwen Zhang
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    1 These authors contributed equally to this article.
    Affiliations
    Department of Quarantine Ward, East District of First Affiliated Hospital of Anhui Medical University (Feidong People's Hospital), Hefei, Anhui Province, China

    Graduate School, Soochow University, Suzhou, Jiangsu Province, China
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    1 These authors contributed equally to this article.
    Xinyue Zhang
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    1 These authors contributed equally to this article.
    Affiliations
    Department of Academic Research, The First People's Hospital of Hefei, Hefei, Anhui Province, China
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  • Author Footnotes
    1 These authors contributed equally to this article.
    Zhijian Wei
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    1 These authors contributed equally to this article.
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    Department of General Surgery, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China
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  • Lingli Zhang
    Affiliations
    Department of Quarantine Ward, East District of First Affiliated Hospital of Anhui Medical University (Feidong People's Hospital), Hefei, Anhui Province, China
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  • Jingjing Xu
    Affiliations
    Department of Quarantine Ward, East District of First Affiliated Hospital of Anhui Medical University (Feidong People's Hospital), Hefei, Anhui Province, China
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  • Peipei Liang
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    Department of Emergency Medicine, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui Province, China
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  • Yuanhong Xu
    Correspondence
    Corresponding authors.
    Affiliations
    Department of Clinical Laboratory Medicine, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China
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  • Chengyuan Zhang
    Correspondence
    Corresponding authors.
    Affiliations
    Department of Respiratory and Critical Care Medicine, East District of First Affiliated Hospital of Anhui Medical University (Feidong People's Hospital), Hefei 231600, Anhui Province, China
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  • Aman Xu
    Correspondence
    Corresponding author at: Department of General Surgery, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China (Aman Xu); Department of Respiratory and Critical Care Medicine, East District of First Affiliated Hospital of Anhui Medical University (Feidong People's Hospital), Hefei 231600, Anhui Province, China (Chengyuan Zhang); Department of Clinical Laboratory Medicine, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China (Yuanhong Xu); Department of General Surgery, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China (Lei Huang).
    Affiliations
    Department of General Surgery, the First Affiliated Hospital of Anhui Medical University, Hefei 230022, Anhui Province, China
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    1 These authors contributed equally to this article.
Published:April 10, 2020DOI:https://doi.org/10.1016/j.jinf.2020.03.006

      Summary

      Background

      The outbreak of coronavirus-disease-2019 (COVID-19) has rapidly spread to many places outside Wuhan. Previous studies on COVID-19 mostly included older hospitalized-adults. Little information on infectivity among and characteristics of youngsters with COVID-19 is available.

      Methods

      A cluster of 22 close-contacts of a 22-year-old male (Patient-Index) including youngsters with laboratory-confirmed COVID-19 and hospitalized close-contacts testing negative for severe-acute-respiratory-syndrome-coronavirus-2 (SARS-CoV-2) in Anhui Province, China was prospectively-traced.

      Results

      Since January 23, 2020, we enrolled a cluster of eight youngsters with COVID-19 (median age [range], 22 [16–23] years; six males) originating from Patient-Index returning from Wuhan to Hefei on January 19. Patient-Index visited his 16-year-old female cousin in the evening on his return, and met 15 previous classmates in a get-together on January 21. He reported being totally asymptomatic and were described by all his contacts as healthy on January 19-21. His very first symptoms were itchy eyes and fever developed at noon and in the afternoon on January 22, respectively. Seven youngsters (his cousin and six classmates) became infected with COVID-19 after a-few-hour-contact with Patient-Index. None of the patients and contacts had visited Wuhan (except Patient-Index), or had any exposure to wet-markets, wild-animals, or medical-institutes within three months. For affected youngsters, the median incubation-period was 2 days (range, 1–4). The median serial-interval was 1 day (range, 0–4). Half or more of the eight COVID-19-infected youngsters had fever, cough, sputum production, nasal congestion, and fatigue on admission. All patients had mild conditions. Six patients developed pneumonia (all mild; one bilateral) on admission. As of February 20, four patients were discharged.

      Conclusions

      SARS-CoV-2-infection presented strong infectivity during the incubation-period with rapid transmission in this cluster of youngsters outside Wuhan. COVID-19 developed in these youngsters had fast onset and various nonspecific atypical manifestations, and were much milder than in older patients as previously reported.

      Keywords

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