Are Lactobacillus Bulgaricus and Bacillus Calmette-Guérin vaccine suitable for patient protection against SARS-CoV-2 infection?

Before COVID-19 infection caused the global pandemic in 2020, coronavirus diseases were mainly of veterinary interest. This pandemic necessitated the development of protective and therapeutic measures against the spread of SARS-CoV-2. Foods containing representatives of the genus Lactobacillus are an integral part of the daily menu of the Bulgarian people. Our hypothesis is based on studies examining its potential for competitive inhibition of viruses and bacteria by attachment to the surface of enterocytes. Bacillus Calmette-Guérin (BCG) is an integral part of the vaccination calendar in the Republic of Bulgaria. In the literature, many clinical studies show that the administration of BCG vaccine limits the SARS-CoV-2 antigens and, consequently, is able to induce protection for COVID-19, by activating the specific, innate immune system. The lack of definitively approved treatment necessitates finding ways to limit the spread of COVID-19 until final drug approval. We believe that the use of dietary components in the context of competitive inhibition and the vaccination schedule for protection in coronavirus-related diseases is applicable. We hypothesize that Lactobacillus and BCG may play a protective effect against SARS-CoV-2 infection alone or in combination in healthy individuals.