Population-Based Study of anti-SARS-CoV-2, Social Distancing and Government Responses in Joinville, Brazil

  1. Henrique Diegoli
  2. Vivianne Samara Conzatti
  3. Suleimy Cristina Mazin
  4. Juliana Safanelli
  5. Louise Domenguini Chiaradia Dellatorre
  6. Keli Bett
  7. Roselaine Elisa Radtke
  8. Giulia Murillo Wollmann
  9. Helbert do Nascimento Lima
  10. Paulo Henrique Condeixa de França
  11. Jean Rodrigues da Silva

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Abstract

Background

The city of Joinville had been mildly affected by the COVID-19 pandemic until June 2020. This study aimed to longitudinally assess the prevalence of exposure to the virus and social distancing practices in the local population.

Methods

A randomized selection of households stratified by region was created. From June 15 to August 7, 2020, a dweller was randomized in each household, answered a questionnaire, and performed a test for the detection of SARS-CoV-2 antibodies. The prevalence of positive tests was calculated for each week and adjusted for the test’s sensitivity and specificity.

Results

The adjusted proportion of positive results increased from 1.4% in the first week (margin of error [ME] 0% to 2.87%) to 13.38% in the eighth week (ME 10.22% to 16.54%). Among the 213 participants that tested positive, 55 (25.82%) were asymptomatic. Only 37 (17.37%) sought medical consultation for any symptom. Among the 77 (36.15%) that were leaving home to work or study, only 18 (23.38%) stopped due to any symptom. The proportion that referred going to bars, restaurants, or making non-essential shopping decreased from 20.56% in the first week to 8.61% during the peak of diagnoses.

Conclusion

The low proportion of participants that sought medical consultation or stopped leaving home indicates strategies directed to isolate only those symptomatic reach a low proportion of infected patients.

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  1. ScreenIT

    SciScore for 10.1101/2021.02.08.21251009: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: The study was approved by a local ethics committee (protocol number 37962620.6.0000.8062).
    RandomizationEvery week, health care professionals and trained volunteers made telephone calls to households previously randomly selected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    The test detects the presence of IgG or IgM antibodies to SARS-CoV-2, and possible results are negative or positive.
    IgM
    suggested: None
    SARS-CoV-2
    suggested: None
    Software and Algorithms
    SentencesResources
    The statistical analyses were conducted using Microsoft Excel 365®.
    Microsoft Excel
    suggested: (Microsoft Excel, RRID:SCR_016137)

    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: A limitation was that the scheduling process was carried out through telephone calls. The process may generate a selection bias in favor of those who have telephone sets and are available to answer the calls. Besides, there was an underrepresentation of residents between 0 and 29 years, and those between 30 and 69 years had a higher representation. On the other hand, an adjustment for age did not substantially change the proportion of residents with a positive test. Besides, the proportion that refused to participate remained similar between regions. The data’s reliability is also strengthened by the high correlation between the total number of positive tests in the city and the prevalence of antibodies in the study.

    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.
    • No funding statement was detected.
    • 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 10.1101/2021.02.08.21251009v1 on medRxiv