Conclusions
The age-associated diseases that appear to be most associated with
severe COVID-19 are also associated with elevated IL-6 and
other inflammatory markers, along with evidence of microbiome dysbiosis
and/or low-grade infection. The imbalances in the immune system arising
from this potentially microbiome-related inflammation are possibly a
contributing factor in the susceptibility to acute viral infection and
the severe cytokine storms that frequently lead to fatal outcomes in
COVID-19.
In the long run, determination of how to achieve an optimal response to
viral infections like COVID-19 will likely benefit from increased
studies on how the microbiome might be shifted toward a more normal,
healthy, youthful state. Based on the research discussed above, this
state would be expected to be associated with a lower likelihood of
severe effects from COVID-19 and other infectious agents, along with
benefit in other debilitating diseases. It would be preferable to
achieve this state with lifestyle and dietary factors; however,
medications, probiotics and other approaches discussed in this review
could also be used if supported by adequate research. To achieve this
goal and the goal of improving COVID-19 outcomes, more research is
clearly needed.