SARS-CoV-2 is a novel infectious contagion leading to
COVID-19
disease. The virus has affected the lives of millions of people across
the globe with a high mortality rate. It predominantly affects the
lung (respiratory system), but it also affects other organs, including
the cardiovascular, psychological, and gastrointestinal (GIT) systems.
Moreover, elderly and comorbid patients with compromised organ functioning
and pre-existing polypharmacy have worsened COVID-19-associated complications.
Microbiota (MB) of the lung plays an important role in developing
COVID-19. The extent of damage mainly depends on the predominance
of opportunistic pathogens and, inversely, with the predominance of
advantageous commensals. Changes in the gut MB are associated with
a bidirectional shift in the interaction among the gut with a number
of vital human organs, which leads to severe disease symptoms. This
review focuses on dysbiosis in the gut–lung axis, COVID-19-induced
worsening of comorbidities, and the influence of polypharmacy on MB.