Can Probiotics, Particularly Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A, Be Preventive Alternatives against SARS-CoV-2?

SIMPLE SUMMARY: Infection with the SARS-CoV-2 virus causes COVID-19 in humans. It has rapidly propagated worldwide, becoming a pandemic as designated by the WHO. SARS-CoV-2 is a single-stranded RNA virus belonging to the family Coronaviridae, subfamily Orthocoronaviridae, characterized by spike (S) proteins, which allow it to bind to the ACE2 receptor present on epithelial cells. Thus, this virus preferably infects tissues that highly express the ACE2 receptor, the lungs and intestine being the most affected, producing an impaired immune response or intestinal dysbiosis, respectively. Presently, treatment against COVID-19 is based on using antivirals, antibiotics to control a secondary bacterial infection, and drugs that attack the symptomatology associated with the infection, alone or combined. Furthermore, several vaccines have been approved that show variable effectiveness, through a diverse number of doses, in confronting the emergence of new SARS-CoV-2 variants; however, this effectivity is affected by the low numbers of vaccinated individuals in developing countries, rates that could increase due to a lack of reinforcements. Considering the present situation, new alternatives with which to treat this problem have been proposed. These alternatives include probiotics, particularly immunobiotics, which can beneficially stimulate intestinal immunity and pulmonary immunity through the intestine–lung axis. ABSTRACT: COVID-19, an infection produced by the SARS-CoV-2 virus in humans, has rapidly spread to become a high-mortality pandemic. SARS-CoV-2 is a single-stranded RNA virus characterized by infecting epithelial cells of the intestine and lungs, binding to the ACE2 receptor present on epithelial cells. COVID-19 treatment is based on antivirals and antibiotics against symptomatology in addition to a successful preventive strategy based on vaccination. At this point, several variants of the virus have emerged, altering the effectiveness of treatments and thereby attracting attention to several alternative therapies, including immunobiotics, to cope with the problem. This review, based on articles, patents, and an in silico analysis, aims to address our present knowledge of the COVID-19 disease, its symptomatology, and the possible beneficial effects for patients if probiotics with the characteristics of immunobiotics are used to confront this disease. Moreover, two probiotic strains, L. fermentum UCO-979C and L. rhamnosus UCO-25A, with different effects demonstrated at our laboratory, are emphasized. The point of view of this review highlights the possible benefits of probiotics, particularly those associated with immunomodulation as well as the production of secondary metabolites, and their potential targets during SARS-CoV-2 infection.