Evidences and perspectives of the use of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention and treatment of COVID-19: A bibliometric analysis and systematic review

Abstract

Background: Coronavirus disease-19 (COVID-19) is an infectious disease transmitted by the virus responsible for the severe acute respiratory syndrome 2 (SARS-CoV-2), which exhibit several clinical manifestations including gastrointestinal symptoms.

Scope and approach: This review aimed to provide insights and perspectives for the use of probiotics, prebiotics, synbiotics, and postbiotics as adjuvants for prevention/treatment and/or modulation of the microbiota in COVID-19 patients. Eighty-four studies published in the Scopus database from the onset of the pandemic until December 2021 were assessed and submitted to a bibliometric analysis adapted from VOSviewer software.

Key findings and conclusions: Through bibliometric analysis, it might be suggested that the modulation of the gut/lung microbiome is promising as an adjuvant for the prevention/treatment of COVID-19 patients, due to immunomodulation properties related to probiotics and prebiotics. So far, few clinical studies involving the application of probiotics in COVID-19 patients have been completed, but reduction in the duration of the disease and the severity of symptoms as fatigue, olfactory dysfunction and breathlessness, nausea and vomiting and other gastrointestinal symptoms were some of the main findings. However, probiotics are not recommended to immunocompromised patients in corticosteroid therapy. The future perspectives point to the modulation of the intestinal microbiota by probiotics, prebiotics, synbiotics, and postbiotics represent a promising adjuvant approach for improving the health of patients with COVID-19.

Keywords: Diet; Functional foods; Gut-lung axis; Immunomodulation; Microbiome; Pandemic.

Graphical abstract

Fig. 1

Countries network according to authorship affiliations. Forty-seven countries were included in the network. Greece, Iraq, Morocco, Russian, South Africa, Taiwan, and Turkey were identified, but showed no co-occurrence network.

Fig. 2

Co-occurrence networks of 45 author keywords which appeared at least two times. The keywords-networks are colored according to the five generated clusters (a) and gradient color (b) which indicates the period of the keywords occurrence from 2020 (blue) to 2021 (yellow). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)

Fig. 3

Co-occurrence networks of terms in title/abstract of selected published papers available in Scopus database. The terms-networks are colored according to the three generated clusters (a) and a gradient color (b) which indicates the period of the terms occurrence from 2020 (blue) to 2021 (yellow). From the 2329 terms, 24 terms have occurred at least 9 times. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)