Sero-prevalence of anti-SARS-CoV-2 Antibodies in Addis Ababa, Ethiopia

  1. Berhanu Nega Alemu
  2. Adamu Addissie
  3. Gemechis Mamo
  4. Negussie Deyessa
  5. Tamrat Abebe
  6. Abdulnasir Abagero
  7. Wondimu Ayele
  8. Workeabeba Abebe
  9. Tewodros Haile
  10. Rahel Argaw
  11. Wondwossen Amogne
  12. Ayele Belachew
  13. Zelalem Desalegn
  14. Brhanu Teka
  15. Eva Kantelhardt
  16. Mesfin Wossen
  17. Saro Abdella
  18. Getachew Tollera
  19. Lia Tadesse

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Abstract

Background

Anti-SARS-CoV-2 antibody tests are being increasingly used for sero-epidemiological purposes to provide better understanding of the extent of the infection in the community, and monitoring the progression of the COVID-19 epidemic. We conducted sero-prevalence study to estimate prior infection with with SARS-CoV-2 in Addis Ababa.

Methods

A cross-sectional study was done from April 23 to 28, 2020 among 301 randomly selected residents of Addis Ababa; with no known history of contact with confirmed COVID-19 person. Interviews on socio demographic and behavioural risk factor followed by serological tests were performed for SARS-CoV-2 IgM, and IgG antibodies, using COVID-19 IgG/IgM Rapid Test Cassette. The test has sensitivity of 87·9% and specificity of 100% for lgM; and a sensitivity of 97·2% and specificity of 100% for IgG. RT-PCR test was also done on combined nasopharyngeal and oropharengeal swabs as an important public health consideration.

Findings

The unadjusted antibody-based crude SARS-CoV-2 prevalence was 7·6% and the adjusted true SARS-CoV-2 prevalence was estimated at 8·8% (95% CI 5·5%-11·6%) for the study population. Higher sero-prevalence were observed for males (9.0%), age below 50 years (8.2%), students and unemployed (15.6%), those with primary education (12.1%), smokers (7.8%), alcohol consumers (8.6%), chatt-chewers (13.6%) and shish smokers (18.8%). Seroprevalence was not significantly associated neither with socio-demographic not behavioral characteristics. According to the findings, possibly more individuals had been infected in Addis Ababa than what was being detected and reported by RT-PCR test suggestive of community transmission. The use of serological test for epidemiological estimation of the extent of SARS-CoV-2 epidemic gives a more precise estimate of magnitude which would be used for further monitoring and surveillance of the magnitude of the SARS CoV-2 infection.

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  1. ScreenIT

    SciScore for 10.1101/2020.10.13.337287: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementConsent: Individuals who were unable to consent, those with unstable mental state and suspected to have acute SARS-CoV-2 infection were excluded.
    RandomizationStudy participants were recruited from the community level randomly through sub-city health extension focal personnel.
    Blindingnot detected.
    Power Analysiswith no close contact with SARS-CoV-2 Infected individuals to be14% based on earlier European studies about the time of the study 18, 80% power and 99% confidence level The Epi Info/Open Epi program is used for the sample size calculation19.
    Sex as a biological variablenot detected.

    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:
    Policy implications: Such serological estimates provide a substantial and comprehensive input to the epidemiologic projections of SARS-CoV-2 especially in a setting where extensive and reliable viral antigen tests are a limitation. In addition, the current and subsequent data will provide evidence for policy makers to make decisions on locally generated evidence. While this possibly the first SARS-CoV-2 sero-prevalence study in Ethiopia (possibly in Africa, there are a number of limitations. The test kit utilized was not validated in our population and the target antigen of the kit is not described by the company. In addition the relatively smaller number subjects included in the study may affect generalisability. The test kit has been validated in Sweden and used for population based studies in Spain and China. In-country validation of the study is currently being done by EPHI but not completed. The serological tests were not primarily done to detect a concurrent active infection with no contribution to SARS-CoV-2 case detection and management purposes.

    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 10.1101/2020.10.13.337287v1 on bioRxiv