SARS-CoV-2 antibody seroprevalence in Tbilisi, the capital city of country of Georgia

  1. Tengiz Tsertsvadze
  2. Lana Gatserelia
  3. Marine Mirziashvili
  4. Natia Dvali
  5. Akaki Abutidze
  6. Revaz Metchurtchlishvili
  7. Carlos el Rio
  8. Nikoloz Chkhartishvili

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Abstract

Background

Georgia timely implemented effective response measures, with testing, contact tracing and isolation being the main pillar of the national response, achieving the lowest cumulative incidence of SARS-CoV-2 in the European region.

Methods

We conducted a survey to estimate SARS-CoV-2 IgG antibody seroprevalence among adult residents of capital city of Tbilisi (adult population: 859,328). Participants were recruited through respondent driven sampling during May 18-27, 2020. Blood specimens were tested for SARS-CoV-2 IgG antibodies using commercially available lateral flow immunoassay (COVID-19 IgG/IgM Rapid Test Cassette, Zhejiang Orient Gene Biotech). Crude seroprevalence was weighted by population characteristics (age, sex, district of Tbilisi) and further adjusted for test accuracy.

Results

Among 1,068 adults recruited 963 (90.2%) were between 18 and 64 years-old, 682 (63.9%) women. 176 (16.5%) reported symptoms indicative of SARS-CoV-2 infection occurring in previous three months. Nine persons tested positive for IgG: crude seroprevalence: 0.84%, (95% CI: 0.33%-1.59%), weighted seroprevalence: 0.94% (95% CI: 0.37%-1.95%), weighted and adjusted for test accuracy: 1.02% (95% CI: 0.38%-2.18%). The seroprevalence estimates translate into 7,200 to 8,800 infections among adult residents of Tbilisi, which is at least 20 times higher than the number of confirmed cases.

Conclusions

Low seroprevalence confirms that Georgia successfully contained spread of SARS-CoV-2 during the first wave of pandemic. Findings also suggest that undocumented cases due to asymptomatic or very mild disease account for majority of infections. Given that asymptomatic persons can potentially spread the virus, test and isolate approach should be further expanded to control the epidemic.

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  1. ScreenIT

    SciScore for 10.1101/2020.09.18.20195024: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Study was approved by the Institutional Review Board of the Infectious Diseases, AIDS and Clinical Immunology Research Center (OHRP #: IRB00006106).
    Consent: Informed consent was obtained from all participants.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    Crude seroprevalence was calculated as the proportion of survey participants testing positive for IgG antibodies.
    IgG
    suggested: None

    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:
    We acknowledge that the prevalence shown in our study might be biased because of limitations related to study design and test-accuracy. Survey was conducted during lockdown and applying probability-based random sampling was not feasible. Instead we used responded driven sampling, which is superior method over simple convenience sampling.28 In addition we offered in-home blood collection to facilitate enrollment in the study with almost 30% of participants opting for this options. However, bias could not be eliminated as we observed underrepresentation of certain population sub-groups, which was addressed by weighting our results by age, gender and district to match the population of Tbilisi. Another potential source of selection of bias is that persons with history of symptoms or contact with confirmed cases may have been more likely to participate to seek antibody confirmation of their potential exposure to SARS-CoV-2. We adjusted our estimates for test accuracy using data from independent validation study,5 however possibility of cross-reaction with other human coronaviruses remains a concern and cannot be ruled out.29–31 Despite these limitations study provides important data for informing public health action. First of all, our results highlight that Georgia’s response strategy succeeded in containing the epidemic. Seroprevalence of 1.02% is significantly lower than those reported from COVID-19 hotspot areas.32 Data also shows that despite strict confinement measures esti...

    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

    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 10.1101/2020.09.18.20195024v1 on medRxiv