Does TB Vaccination Reduce COVID-19 Infection? No Evidence from a Regression Discontinuity Analysis

  1. Masao Fukui
  2. Kohei Kawaguchi
  3. Hiroaki Matsuura

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Abstract

In the middle of the global COVID-19 pandemic, the BCG hypothesis, the prevalence and severity of the COVID-19 outbreak seems to be correlated with whether a country has a universal coverage of Bacillus-Calmette-Guérin (BCG), a vaccine for tuberculosis disease (TB), has emerged and attracted the attention of scientific community and media outlets. However, all existing claims are based on cross-country correlations that do not exclude the possibility of spurious correlation. We merged country-age-level case statistics with the start/termination years of BCG vaccination policy and conducted a regression discontinuity and difference-indifference analysis. The results do not support the BCG hypothesis.

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  1. ScreenIT

    SciScore for 10.1101/2020.04.13.20064287: (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: Thank you for sharing your code and data.

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    There are three limitations to our analysis. First, our analysis focused on the effect on COVID-19 infection due to the data availability. BCG immunization can still prevent from developing symptoms or reduce death once infected by COVID-19. However, given that those with COVID-19 symptoms and their close contacts are more likely to be tested and confirmed, we still capture some effects of BCG immunization on developing symptoms. Second, there is possibility that population (in addition to individual) immunity affects our COVID-19 outcomes. However, we removed out potential population immunity effects of the BCG vaccination by controlling for country-specific unobserved fixed effects. We agree that population immunity effects are another parameter of policy interest. However, we leave this to the future research. Another potential criticism is that people acquired immunity from the actual infection of TB, rather than the BCG immunization. If the effects of the BCG immunization and TB on the COVID-19 infection are the same and the TB infection rate was almost 100% around the change in the vaccination policy, there is a possibility that we failed to pick up any additional effects of the BCG immunization. However, this is implausible. Marks et al. (2018) document that in Vietnam, only around 30-40% of age 30s and 40-50% of older population are infected by TB in 2016. In Thailand, the infection rate of children under 14 years old in 1977, when the vaccination started, was 15.2% (...

    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 10.1101/2020.04.13.20064287v1 on medRxiv