ABSTRACT
BACKGROUND: Viral respiratory infections could result in perturbation of the gut microbiota due to a probable cross-talk between lungs and gut microbiota. This can affect pulmonary health and the gastrointestinal system. OBJECTIVE: This review aimed to discuss the impact of probiotics/prebiotics and supplements on the prevention and treatment of respiratory infections, especially emerging pathogens. METHODS: The data were searched in PubMed, Scopus, Google Scholar, Google Patents, and The Lens-Patent using keywords of probiotics and viral respiratory infections in the title, abstract, and keywords. RESULTS: Probiotics consumption could decrease the susceptibility to viral respiratory infections, such as COVID-19 and simultaneously enhance vaccine efficiency in infectious disease prevention through the immune system enhancement. Probiotics improve the gut microbiota and the immune system via regulating the innate system response and production of anti-inflammatory cytokines. Moreover, treatment with probiotics contributes to intestinal homeostasis restitution under antibiotic pressure and decreasing the risk of secondary infections due to viral respiratory infections. Probiotics present varied performances in different conditions; thus, promoting their efficacy through combining with supplements (prebiotics, postbiotics, nutraceuticals, berberine, curcumin, lactoferrin, minerals, and vitamins) is important. Several supplements reported to enhance the probiotics' efficacy and their mechanisms as well as probiotics- related patents are summarized in this review. Using nanotechnology and microencapsulation techniques can also improve probiotics' efficiency. CONCLUSION: Given the global challenge of COVID-19, probiotic/prebiotic and following nutritional guidelines should be regarded seriously. Additionally, their role as an adjuvant in vaccination for immune response augmentation needs attention.