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

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. JEL: I18, I15.

Time-adjusted Analysis Shows Weak Associations Between BCG Vaccination Policy and COVID-19 Disease Progression

“…While some of the previous studies have observed associations between BCG vaccination policy and spread of COVID-19 (Miller et al, 2020; Berg et al, 2020), others criticized their work and showed that after corrections for various covariate factors, no statistically significant associations could be found Hensel et al (2020); Fukui et al (2020); Singh (2020). Most of these studies have used indicators that were quite straightforward, such as the number of reported cases per million inhabitants on a particular date.…”

“…The associations between BCG vaccination policy and COVID-19 disease progression have also been a subject to controversy in data analysis, with some studies claiming significant effects on the number of cases and case fatality rates (Miller et al, 2020; Berg et al, 2020), while others criticizing weaknesses of those studies and claiming no statistically significant differences (Szigeti et al, 2020; Hensel et al, 2020; Fukui et al, 2020; Singh, 2020).…”

Social Distancing, Temperature, BCG and the Evolution of COVID-19: A Panel-Model Analysis

“…To construct this variable, we initially attributed a value of zero to countries that have never had public vaccination policy for BCG (examples: USA and Italy) 12 . Next, for countries that have an active vaccination program (Brazil and China), the historical average percentage of BCG coverage was used 13 .…”

“…It led to approximately 281 thousand immune people died. Subtracting this number from 12 http://www.bcgatlas.org. 13 https://www.who.int/data/gho/indicator-metadata-registry/imr-details/2442.…”

Current national policies for infant universal bacille Calmette-Guérin vaccination were associated with lower mortality from coronavirus disease 2019

“…Some advocated that BCG-vaccinated people are less suffered from the virus because COVID-19 high burden countries such as Italy, Spain, USA, and France do not currently recommend universal BCG vaccination [ 2 3 4 ]. However, the others objected because this seemingly attractive relationship is explainable with confounding factors such as aged society, resource rich medical system to detect COVID-19, lower temperature, and advanced reporting system of COVID-19 high-burden tuberculosis (TB) low-burden countries [ 5 6 ]. We assessed if country-level universal BCG vaccination policy was associated with decreased mortality from COVID-19 after adjusting multiple possible confounding factors.…”