The bacillus Calmette-Guérin vaccination allows the innate immune system to provide protection from severe COVID-19 infection.

We have read the paper by Escobar et al. (1), and we also support a similar hypothesis (2), which arose from the observation of the so-called Iberian Peninsula paradox. As they also report, in the same geographical area with similar socioeconomic conditions, completely different and particularly high mortality rates have been observed in Spain where tuberculosis vaccination is not mandatory, unlike Portugal (3⇓–5) (Fig.1)\n\n\n\nFig. 1. \nMap displaying bacillus Calmette–Guerin vaccination policy by country. ( A ) The country currently has universal bacillus Calmette–Guerin vaccination program. ( B ) The country used to recommend bacillus Calmette–Guerin vaccination for everyone but currently does not. ( C ) The country never had universal bacillus Calmette–Guerin vaccination programs. Reprinted from ref. (4), which is licensed under CC BY 4.0.\n\n\n\nRecently, we conducted a study on Italian … \n\n[↵][1]1To whom correspondence may be addressed. Email: info{at}allergiasalerno3.it.\n\n [1]: #xref-corresp-1-1