Occupational risk of COVID-19 in the first versus second epidemic wave in Norway, 2020

  1. Karin Magnusson
  2. Karin Nygård
  3. Fredrik Methi
  4. Line Vold
  5. Kjetil Telle

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Abstract

The occupational risk of COVID-19 may be different in the first versus second epidemic wave.

Aim

To study whether employees in occupations that typically entail close contact with others were at higher risk of SARS-CoV-2 infection and COVID-19-related hospitalisation during the first and second epidemic wave before and after 18 July 2020, in Norway.

Methods

We included individuals in occupations working with patients, children, students, or customers using Standard Classification of Occupations (ISCO-08) codes. We compared residents (3,559,694 on 1 January 2020) in such occupations aged 20–70 years (mean: 44.1; standard deviation: 14.3 years; 51% men) to age-matched individuals in other professions using logistic regression adjusted for age, sex, birth country and marital status.

Results

Nurses, physicians, dentists and physiotherapists had 2–3.5 times the odds of COVID-19 during the first wave when compared with others of working age. In the second wave, bartenders, waiters, food counter attendants, transport conductors, travel stewards, childcare workers, preschool and primary school teachers had ca 1.25–2 times the odds of infection. Bus, tram and taxi drivers had an increased odds of infection in both waves (odds ratio: 1.2–2.1). Occupation was of limited relevance for the odds of severe infection, here studied as hospitalisation with the disease.

Conclusion

Our findings from the entire Norwegian population may be of relevance to national and regional authorities in handling the epidemic. Also, we provide a knowledge foundation for more targeted future studies of lockdowns and disease control measures.

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  1. Version published to 10.2807/1560-7917.es.2021.26.40.2001875
  2. ScreenIT

    SciScore for 10.1101/2020.10.29.20220426: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Institutional board review was conducted, and the Ethics Committee of South-East Norway confirmed (June 4th 2020, #153204) that external ethical board review was not required.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    The statistical software used was STATA MP v.16.
    STATA
    suggested: (Stata, RRID:SCR_012763)

    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:
    Some important limitations should be mentioned. First, we cannot exclude that other factors than the occupation in question explain infection and hospitalization risks in our study. As an example, persons in full-employment may be at greater risk of COVID-19 than persons in part-time employment. Also, we cannot be sure we have sufficiently adjusted for other risk factors related to e.g. country of birth, residential area, risky behavior and health literacy, which may be of particular relevance to our analyses of hospitalization [8]. Further, it is possible that employees working and living close together in small areas (more typical for big cities) may be infected by each other rather than by the customers/children/patients they meet [17]. Indeed, point estimates and their 95% CI were generally lowered in adjusted compared to crude analyses, suggesting that occupation and our outcomes are partly explained by sociodemographic factors. Our stratified analyses may shed further light on the differences in occupational risk in rural and urban areas (S-Figure A-K). However, we had sparse data in several of the counties studied, and the county-specific analyses should be interpreted with caution due to low numbers. Another potential limitation is the validity of negative tests in the beginning of the pandemic, before April 1st 2020. Finally, we converted the Norwegian occupation classification to ISCO-08 and some of the occupations (0.3%) were lost as they did not convert to the int...

    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 10.1101/2020.10.29.20220426v2 on medRxiv
  4. Version published to 10.1101/2020.10.29.20220426v1 on medRxiv