BCG Vaccination and Mortality of COVID-19 across 173 Countries: An Ecological Study

Mitsuyoshi Urashima, Katharina Otani, Yasutaka Hasegawa and Taisuke Akutsu
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Mitsuyoshi Urashima: Division of Molecular Epidemiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan
Katharina Otani: Division of Molecular Epidemiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan
Yasutaka Hasegawa: Division of Molecular Epidemiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan
Taisuke Akutsu: Division of Molecular Epidemiology, The Jikei University School of Medicine, Tokyo 105-8461, Japan

IJERPH, 2020, vol. 17, issue 15, 1-20

Abstract: Ecological studies have suggested fewer COVID-19 morbidities and mortalities in Bacillus Calmette–Guérin (BCG)-vaccinated countries than BCG-non-vaccinated countries. However, these studies obtained data during the early phase of the pandemic and did not adjust for potential confounders, including PCR-test numbers per population (PCR-tests). Currently—more than four months after declaration of the pandemic—the BCG-hypothesis needs reexamining. An ecological study was conducted by obtaining data of 61 factors in 173 countries, including BCG vaccine coverage (%), using morbidity and mortality as outcomes, obtained from open resources. ‘Urban population (%)’ and ‘insufficient physical activity (%)’ in each country was positively associated with morbidity, but not mortality, after adjustment for PCR-tests. On the other hand, recent BCG vaccine coverage (%) was negatively associated with mortality, but not morbidity, even with adjustment for percentage of the population ? 60 years of age, morbidity, PCR-tests and other factors. The results of this study generated a hypothesis that a national BCG vaccination program seems to be associated with reduced mortality of COVID-19, although this needs to be further examined and proved by randomized clinical trials.

Keywords: urbanization; Bacillus Calmette–Guérin; BCG; vaccination; coronavirus disease 2019; COVID-19; SARS-CoV-2; ecological study; morbidity; mortality (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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