Estimation of SARS-CoV-2 Infection Fatality Rate by Real-time Antibody Screening of Blood Donors

  1. Christian Erikstrup
  2. Christoffer Egeberg Hother
  3. Ole Birger Vestager Pedersen
  4. Kåre Mølbak
  5. Robert Leo Skov
  6. Dorte Kinggaard Holm
  7. Susanne Gjørup Sækmose
  8. Anna Christine Nilsson
  9. Patrick Terrence Brooks
  10. Jens Kjærgaard Boldsen
  11. Christina Mikkelsen
  12. Mikkel Gybel-Brask
  13. Erik Sørensen
  14. Khoa Manh Dinh
  15. Susan Mikkelsen
  16. Bjarne Kuno Møller
  17. Thure Haunstrup
  18. Lene Harritshøj
  19. Bitten Aagaard Jensen
  20. Henrik Hjalgrim
  21. Søren Thue Lillevang
  22. Henrik Ullum

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Abstract

Background

The pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has tremendous consequences for our societies. Knowledge of the seroprevalence of SARS-CoV-2 is needed to accurately monitor the spread of the epidemic and to calculate the infection fatality rate (IFR). These measures may help the authorities make informed decisions and adjust the current societal interventions. The objective was to perform nationwide real-time seroprevalence surveying among blood donors as a tool to estimate previous SARS-CoV-2 infections and the population-based IFR.

Methods

Danish blood donors aged 17–69 years giving blood 6 April to 3 May were tested for SARS-CoV-2 immunoglobulin M and G antibodies using a commercial lateral flow test. Antibody status was compared between geographical areas, and an estimate of the IFR was calculated. Seroprevalence was adjusted for assay sensitivity and specificity taking the uncertainties of the test validation into account when reporting the 95% confidence intervals (CIs).

Results

The first 20 640 blood donors were tested, and a combined adjusted seroprevalence of 1.9% (95% CI, .8–2.3) was calculated. The seroprevalence differed across areas. Using available data on fatalities and population numbers, a combined IFR in patients <70 years is estimated at 89 per 100 000 (95% CI, 72–211) infections.

Conclusions

The IFR was estimated to be slightly lower than previously reported from other countries not using seroprevalence data. The IFR is likely severalfold lower than the current estimate. We have initiated real-time nationwide anti–SARS-CoV-2 seroprevalence surveying of blood donations as a tool in monitoring the epidemic.

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  1. Version published to 10.1093/cid/ciaa849
  2. ScreenIT

    SciScore for 10.1101/2020.04.24.20075291: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board Statementnot detected.Randomizationnot detected.Blindingnot detected.Power Analysisnot detected.Sex as a biological variablenot detected.

    Table 2: Resources

    Antibodies
    SentencesResources
    SARS-CoV-2 IgG and IgM antibodies were tested on EDTA plasma or whole blood by a lateral flow test according to the manufacturer’s recommendations ( IgM/IgG Antibody to SARS-CoV-2 lateral flow test , Livzon Diagnostics Inc .
    IgM
    suggested: None
    Software and Algorithms
    SentencesResources
    Statistics Statistical analysis was performed in RStudio 1.2 and R 3.6.0 .
    RStudio
    suggested: (RStudio, SCR_000432)

    Results from OddPub: We did not find a statement about open data. We also did not find a statement about open code. Researchers are encouraged to share open data when possible (see Nature blog).

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  3. Version published to 10.1101/2020.04.24.20075291v1 on medRxiv