SARS‐CoV‐2 re‐infection risk in Austria

  1. Stefan Pilz
  2. Ali Chakeri
  3. John PA Ioannidis
  4. Lukas Richter
  5. Verena Theiler‐Schwetz
  6. Christian Trummer
  7. Robert Krause
  8. Franz Allerberger

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Abstract

Background

A key question concerning coronavirus disease 2019 (COVID‐19) is how effective and long lasting immunity against this disease is in individuals who were previously infected with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). We aimed to evaluate the risk of SARS‐CoV‐2 re‐infections in the general population in Austria.

Methods

This is a retrospective observational study using national SARS‐CoV‐2 infection data from the Austrian epidemiological reporting system. As the primary outcome, we aim to compare the odds of SARS‐CoV‐2 re‐infections of COVID‐19 survivors of the first wave (February to April 30, 2020) versus the odds of first infections in the remainder general population by tracking polymerase chain reaction (PCR)‐confirmed infections of both groups during the second wave from September 1 to November 30, 2020. Re‐infection counts are tentative, since it cannot be excluded that the positive PCR in the first and/or second wave might have been a false positive.

Results

We recorded 40 tentative re‐infections in 14 840 COVID‐19 survivors of the first wave (0.27%) and 253 581 infections in 8 885 640 individuals of the remaining general population (2.85%) translating into an odds ratio (95% confidence interval) of 0.09 (0.07 to 0.13).

Conclusions

We observed a relatively low re‐infection rate of SARS‐CoV‐2 in Austria. Protection against SARS‐CoV‐2 after natural infection is comparable with the highest available estimates on vaccine efficacies. Further well‐designed research on this issue is urgently needed for improving evidence‐based decisions on public health measures and vaccination strategies.

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  1. ScreenIT

    SciScore for 10.1101/2021.02.08.21251362: (What is this?)

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

    Table 1: Rigor

    EthicsIRB: 15 Ethical approval for this study was obtained from the ethics committee at the Medical University of Graz, Graz,
    Sex as a biological variablenot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical analyses were performed by using SPSS Version 25.0 (
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    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:
    Another limitation of our work is that we did not have access to viral sequencing data to compare first and re-infections, and it is not known how well our findings generalize to the re-infection risk concerning different genetic variants of SARS-CoV-2. Finally, we have to stress that our main findings are only a rough estimate of SARS-CoV-2 re-infection risk, requiring urgent confirmation in other populations and study settings. In conclusion, we observed a relatively low tentative re-infection rate of SARS-CoV-2 in Austria that suggests a similar protection against SARS-CoV-2 infection compared to vaccine efficacies.5,19,20 These data may be useful for decisions on public health measures and vaccination strategies to fight the COVID-19 pandemic.2,19,20,23,24 Further studies are urgently needed to improve our knowledge on SARS-CoV-2 re-infection risk and its predisposing factors and clinical significance.

    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.

    Results from scite Reference Check: We found no unreliable references.

    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 10.1111/eci.13520
  3. Version published to 10.1101/2021.02.08.21251362 on medRxiv