Vitamin D and immune response against severe acute respiratory syndrome coronavirus 2 in older adults: Does it really work?

Coronavirus disease 2019 was announced as a pandemic by the WHO on 11 February 2020. Since that time, challenges have arisen regarding the use of supplements to optimally support the immune system in the general population, and especially in older adults. The severity of severe acute respiratory syndrome coronavirus 2 infection varies significantly with age, being generally more severe in geriatric patients. There is evidence supporting the involvement of vitamin D in different processes related to the immune response. Some observational studies have related the decrease in vitamin D levels to the severity of coronavirus disease 2019, suggesting a protective role of vitamin D in this disease. In this narrative review, we analyze the possible role of vitamin D in modulating the immune mechanisms that are activated during severe acute respiratory syndrome coronavirus 2 infection, with special emphasis on older adults.Copyright © 2022 Lippincott Williams and Wilkins. All rights reserved.

The gut microbiome and severity of SARS-CoV-2 infection: what is the link?

In the recent years, studies of the human microbiome have aroused great interest. Several evidences suggest a connection between the gut microbiome and the human immune response at the pulmonary level, which has been defined as the "gut-lung axis". The clinical symptoms of COVID-19 are varied and include gastrointestinal manifestations such as diarrhea, which has been linked to alterations in the gut microbiome;imbalance of the immune response;and delayed viral clearance. The aim of this narrative review was to address the role of the gut microbiome in the respiratory health and in particular, its association with the severity of COVID-19. The gut microbiome plays several important roles therefore;its balance is determinant for the human health, due to its relationship with several essential physiological processes, including maturation of both of the innate and the adaptive immune responses. Intestinal dysbiosis has an impact on the respiratory mucosa, and in turn on infection of the intestinal epithelial cells by SARS-CoV-2, which can induce intestinal inflammation and gastrointestinal symptoms. All these symptoms could contribute to an altered inflammatory immune response to SARS-CoV-2, favoring infection, dissemination and severity of the disease. Knowledge about the roles of the gut microbiome and its interactions in the context of SARS-CoV-2 infection could help to find biomarkers involved in COVID-19-related dysbiosis, as well as to determine the possible therapeutic targets for treatment of these patients. © 2022, Egyptian Association for Medical Mycologists (EAMM). All rights reserved.