Connecting BCG Vaccination and COVID-19: Additional Data

  1. Devi Dayal
  2. Saniya Gupta

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Abstract

The reasons for a wide variation in severity of coronavirus disease 2019 (COVID-19) across the affected countries of the world are not known. Two recent studies have suggested a link between the BCG vaccination policy and the morbidity and mortality due to COVID-19. In the present study we compared the impact of COVID-19 in terms of case fatality rates (CFR) between countries with high disease burden and those with BCG revaccination policies presuming that revaccination practices would have provided added protection to the population against severe COVID-19. We found a significant difference in the CFR between the two groups of countries. Our data further supports the view that universal BCG vaccination has a protective effect on the course of COVID-19 probably preventing progression to severe disease and death. Clinical trials of BCG vaccine are urgently needed to establish its beneficial role in COVID-19 as suggested by the epidemiological data, especially in countries without a universal BCG vaccination policy.

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  1. ScreenIT

    SciScore for 10.1101/2020.04.07.20053272: (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

    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 limitation of our study was the calculation of CFR by dividing the number of known deaths by the number of confirmed cases which may not represent the true CFR during an ongoing epidemic (14). We chose this calculation as both the numerator and denominator were rapidly changing and the use was meant only for comparison and not for projecting the mortality due to COVID-19. We also wish to caution against oversimplification of interpretation of BCG vaccination link with COVID-19 as this is derived from the epidemiological data that needs to be confirmed by well designed clinical trials. Furthermore, the CFR depends on multiple factors, in particular, on the ability of the national governments and the healthcare systems to respond to the epidemic. As COVID-19 gains further foothold in low resource countries, the CFR may change significantly and the current conclusions may then become invalid. Several low resource countries such as India practice universal BCG vaccination policy established since mid-twentieth century. Unlike developed countries where the tuberculosis rates in the population declined significantly prompting their policy makers to adopt a target BCG vaccination approach for high risk populations, the universal vaccination strategy has continued in several high-TB-burden countries (8). The observations of the two recent epidemiological studies alongwith our own data offer hope for a reduced impact of COVID-19 for countries which practice universal BCG vaccination...

    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

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  2. Version published to 10.1101/2020.04.07.20053272v2 on medRxiv
  3. Version published to 10.1101/2020.04.07.20053272v1 on medRxiv