Source and symptoms of COVID-19 among hospital workers in Milan

  1. S Mandić-Rajčević
  2. F Masci
  3. E Crespi
  4. S Franchetti
  5. A Longo
  6. I Bollina
  7. S Velocci
  8. A Amorosi
  9. R Baldelli
  10. L Boselli
  11. L Negroni
  12. A Zà
  13. N V Orfeo
  14. G Ortisi
  15. S Centanni
  16. C Colosio

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Abstract

Background

Healthcare workers (HCWs) are commonly infected by SARS-CoV-2 and represent one of the most vulnerable groups. Adequate prevention strategies are necessary to guarantee HCWs’ safety, as well as to prevent dissemination of the infection among patients.

Aims

To describe a case series of SARS-CoV-2-positive HCWs in a large public healthcare organization in Milan (Italy) during the most devastating weeks of the epidemic and analyse the sources, symptoms and duration of SARS-CoV-2 infection.

Methods

This study included 172 SARS-CoV-2-positive HCWs who were infected between the 25th of February and the 7th of April 2020. A nasopharyngeal swab (NPS) and RT-PCR were used to indicate.

Results

Initially, the most common sources of infection were other positive HCWs (49%). Medical doctors and nursing assistants were most frequently infected, with infection rates of 53/1000 and 50/1000, respectively. COVID-19 departments were less affected than internal medicine, surgery, intensive care, or emergency room. The most commonly reported symptom was mild cough, while loss of smell (anosmia) and loss of taste (ageusia) were reported as moderate and severe by 30–40% of HCWs. The time necessary for 50% of workers to recover from the infection was 23 days, while it took 41 days for 95% of HCWs to become virus-free.

Conclusions

HCWs are commonly infected due to close contacts with other positive HCWs, and non-COVID departments were most affected. Most HCWs were asymptomatic or subclinical but contact tracing and testing of asymptomatic HCWs help identify and isolate infected workers.

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  1. Version published to 10.1093/occmed/kqaa201
  2. ScreenIT

    SciScore for 10.1101/2020.05.03.20082818: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: Nevertheless, all our workers are informed about our health surveillance procedures and have signed an informed consent regarding the data collection and analysis.
    IRB: No ethical approval was deemed necessary by the Ethical Committee of the Saints Paolo and Carlo Hospitals.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variableOut of 5,700 workers, 70% are female, with a mean age of 46 years.

    Table 2: Resources

    No key resources detected.

    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:
    A limitation is the fact that 42 HCWs never filled in even one daily symptoms report. In a telephone survey currently in progress, the most common reasons for not filling the online symptoms report was the lack of a smartphone, computer or internet at home, lack of experience with online forms (“not being technological enough”), being diagnosed in the week prior to the implementation of the online report, and taking care of a sick family member (“lack of time for the reports”). Five HCWs did not fill the report because they were hospitalized. Their reports would certainly differ from the rest of our workers with a mild clinical picture, but heir percentage (less than 5% of 185), similar to that in Madrid where 29 out of 791 required hospitalization, leads us to believe that the data presented are representative of the majority SARS-CoV-2-positive HCWs and the selection bias in our report is negligible. Future studies should analyse in more detail the circumstances surrounding the infection of HCWs, symptoms, and the overall outcome of their disease. New symptoms, such as anosmia and dysgeusia which were frequently reported by our HCWs could help clinicians arrive to a diagnosis sooner and reduce the time available for worker-to-worker and worker-to-patient transfer of SARS-CoV-2. Another step forward will be understanding whether HCWs have developed specific immunity, even among those with negative swab results. This could help us understand whether the presence of specific I...

    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

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  3. Version published to 10.1101/2020.05.03.20082818v1 on medRxiv