**6. Conclusions**

Over a century ago, in his book, Metchnikoff [123] suggested that the manipulation of the gut microbiota could prolong life. A dysregulated immune response may cause lung immunopathology. Strategies to combat multifaceted COVID-19 could be to reduce age-associated inflammation, delay the onset of disease inflammation and prolong life. The functional state of the elderly, their dysbiotic condition, immune-compromised with nutritional deficiencies constitutes as a whole, a condition of extreme vulnerability.

Intestinal microbiota dysbiosis is strongly associated with the pathogenesis of several metabolic and inflammatory diseases and the control of the intestinal microbiota could represent a certain challenge to COVID-19, now and even later, in the consequences that SARS-CoV-2 will bring on the general population.

Changes in the microbial population of the elderly and the associated decline in intestinal tissue function can fuel a chronic state of inflammation, resulting in a vicious cycle that further affects host–microbiome interactions and amplifies the frailty of the elderly. On the other hand, chronic immune stimulation as a consequence of silent systemic inflammation and changes in the metabolome and microbial stimuli contribute to immune senescence.

**Funding:** This research received no external funding.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Conflicts of Interest:** The author declares no conflict of interests.
