Community-level SARS-CoV-2 Seroprevalence Survey in urban slum dwellers of Buenos Aires City, Argentina: a participatory research

  1. Silvana Figar
  2. Vanina Pagotto
  3. Lorena Luna
  4. Julieta Salto
  5. Magdalena Wagner Manslau
  6. Alicia S. Mistchenko
  7. Andrea Gamarnik
  8. Ana María Gómez Saldaño
  9. Fernán González Bernaldo de Quirós

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Abstract

Background

By July 1st, the incidence rate of RT-qPCR SARS-CoV-2 infection was 5.9% in Barrio Padre Mugica, one of the largest slums in Buenos Aires City. This study aimed to establish the seroprevalence of SARS-CoV-2 three months after the first case was reported.

Methods

Between June 10 th and July 1 st , a cross-sectional design was carried out on people over 14 years old, selected from a probabilistic sample of households. A finger prick sample was tested by ELISA to detect IgG-class antibodies against SARS-CoV-2. Multilevel model was applied to understand sector, household and individual conditions associated with seroconvert.

Results

Prevalence based on IgG was 53.4% (95%IC 52.8% to 54.1%). Among the IgG positive cases, 15% reported having compatible symptoms at some point in the past two months. There is evidence of within-household clustering effect (rho=0.52; 95% IC 0.36-0.67); living with a PCR-confirmed case doubled the chance of being SARS-CoV2 IgG positive (OR 2.13; 95% IC 1.17-3.85). The highest risk of infection was found in one of the most deprived areas of the slum, the “Bajo autopista” sector.

Discussion

High seroprevalence is shown, for each symptomatic RT-qPCR-confirmed diagnosis, 9 people were IgG positive, indicating a high rate of undetected (probable asymptomatic) infections. Given that transmission among family members is a leading driver of the disease’s spread, it is unsurprising that crowded housing situations in slums are directly associated with higher risk of infection and consequently high seroprevalence levels.

This study contributes to the understanding of population immunity against SARS-CoV2, its relation to living conditions and viral spread, for future decision making.

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  1. ScreenIT

    SciScore for 10.1101/2020.07.14.20153858: (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 the institutional review board of the “Hospital de Niños “Dr R.
    Consent: Oral informed consent was obtained from every participant.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablePopulation of the study were inhabitants of Barrio Mugica: men and women form 14 years of age or older were included.

    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 caveat must be kept in mind since sex was not an statistical significant variable, male subjects between 14 and 19 years showed the highest prevalence of IgG positives compared with the other groups. Due to the high virus transmission found in our study, we would have expected a higher lethality rate. Bonofiglio et al. have shown that in Barrio Mugica 1.5% of people are older than 65 vs 17% in the rest of Buenos Aires City, with a higher working-age population (37% vs 30%), As a working-class neighborhood it has high immigration and elders stay living in their places of origin [9]. In our study, we also found a low proportion of elderly people (4.5%), these differences with the rest of CABA and other european cities could express that, beside a high virus transmission, the lethality rate was not as high as reported in other countries. For future comparison with other countries, we also informed the standardized prevalence, applying WHO population by age and sex was 54.33 (IC95% 53.2 - 55.5). This study shows the relevance of clustering: cluster correlation was evident among household members who share exposure to COVID-19. In this regard, those who had a family member diagnosed by PCR had two fold chance of becoming infected by the virus. We also found sector differences, those living in worse conditions (“Bajo autopista”, Figure 2) had a higher rate of infection. This could be associated with lack of water supply suffered in April which put the whole community in distressi...

    Results from TrialIdentifier: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    NCT04472078CompletedSeroprevalence of Coronavirus Disease 2019 (COVID-19) Antibo…

    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. ScreenIT

    SciScore for 10.1101/2020.07.14.20153858: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementThe study was approved by the institutional review board of the “Hospital de Niños “Dr R.Randomizationnot detected.Blindingnot detected.Power Analysisnot detected.Sex as a biological variablePopulation of the study were inhabitants of Barrio Mugica: men and women form 14 years of age or older were included.

    Table 2: Resources

    Data from additional tools added to each annotation on a weekly basis.

    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 is not a substitute for expert review. SciScore checks for the presence and correctness of RRIDs (research resource identifiers) in the manuscript, and detects sentences that appear to be missing RRIDs. SciScore also checks to make sure that rigor criteria are addressed by authors. It does this by detecting sentences that discuss criteria such as blinding or power analysis. SciScore does not guarantee that the rigor criteria that it detects are appropriate for the particular study. Instead it assists authors, editors, and reviewers by drawing attention to sections of the manuscript that contain or should contain various rigor criteria and key resources. For details on the results shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.07.14.20153858 on medRxiv