Stop playing with data: there is no sound evidence that Bacille Calmette-Guérin may avoid SARS-CoV-2 infection (for now).

Stop playing with data: there is no sound evidence that Bacille Calmette-Guérin may avoid SARS-CoV-2 infection (for now).


  • Matteo Riccò AUSL-IRCCS di Reggio Emilia V.le Amendola n.2 - 42122 RE Servizio di Prevenzione e Sicurezza negli Ambienti di Lavoro (SPSAL)Dip. di Prevenzione
  • Giovanni Gualerzi University of Parma, Department of Medicine and Surgery, School of Medicine; Via Gramsci n.14, 43123; Parma (PR), Italy
  • Silvia Ranzieri University of Parma, Department of Medicine and Surgery, School of Occupational Medicine; Via Gramsci n.14, 43123; Parma (PR), Italy
  • Nicola Luigi Bragazzi Laboratory for Industrial and Applied Mathematics (LIAM), Department of Mathematics and Statistics, York University, Toronto, Canada


BCG Vaccine, COVID-19, Correlation of Data, Incidence, Mortality, Tuberculosis


Since the beginning of the COVID-19 epidemic, a possible explanation for the high heterogeneity of infection/mortality rates across involved countries was hinted in the prevalence of tuberculosis vaccination with Bacille Calmette-Guérin (BCG). A systematic review was therefore performed on May 2, 2020. A total of 13 articles were ultimately retrieved, 12 of them as preprint papers. All articles were ecological studies of low quality. Most of them did not include main confounding factors (i.e. demographic of the assessed countries, share of peo- ple residing in urban settings, etc.), and simply assessed the differences among incidence/mortality of COVID-19 with vaccination rates or by having vs. having not any vaccination policy for BCG. Even though all studies shared the very same information sources (i.e. international registries for BCG vaccination rates and open source data for COVID-19 epidemics), results were conflicting, with later studies apparently denying any true correlation between COVID-19 occurrence and BCG vaccination rates and/or policies. As a consequence, there is no sound evidence to recommend BCG vaccination for the prevention of COVID-19. 

Author Biography

Matteo Riccò, AUSL-IRCCS di Reggio Emilia V.le Amendola n.2 - 42122 RE Servizio di Prevenzione e Sicurezza negli Ambienti di Lavoro (SPSAL)Dip. di Prevenzione

Dipartimento di Sanità Pubblica

Dirigente Medico di Medicina del Lavoro


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Coronavirus (COVID-19) confirmed cases in Russia as of May 3, 2020, by region (accessed on May 4, 2020)







How to Cite

Stop playing with data: there is no sound evidence that Bacille Calmette-Guérin may avoid SARS-CoV-2 infection (for now). Acta Biomed [Internet]. 2020 May 11 [cited 2024 May 22];91(2):207-13. Available from:

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