Exploring the microbiome’s potential role in severe COVID-19: possible implications for prevention and treatment

Abstract

The human microbiome, especially the microbiomes of the gastrointestinal and respiratory tracts, are potentially important in determining susceptibility to COVID-19 and the immunopathology that leads to severe disease. Data is beginning to be gathered on the risk factors for severe disease in the coronavirus disease of 2019 . This data will be discussed in connection with some highlights of what is being learned about the human microbiome and its relationship with viral illnesses and inflammation-related chronic diseases. In particular, possible roles for diet, lifestyle, and microbiota manipulation as means of reducing rates of severe viral disease will be explored. Some potential pharmaceutical approaches to treating severe COVID-19 disease, involving the microbiome, mast cells and hypersensitivity responses, are also discussed. It is proposed that chronic low-grade infections and/or dysbiosis may underlie the age-related diseases that are risk factors for severe disease from SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2). It is also suggested that the connection between these chronic diseases and COVID-19 may have implications for understanding some of the reasons for the severity of COVID-19 in a proportion of patients. Whether or not the hypothesis of a causal role for dysbiosis or prior infection is correct, some of the suggested treatment approaches might still be worth investigating.

The Post-hunter-gatherer Era Microbes Hypothesis for Chronic Inflammatory Diseases

“…Cardiovascular disease, diabetes and chronic lung diseases have been associated with greater mortality from COVID-19 [273]. These comorbid diseases have all been associated with low grade inflammation, air pollution, a westernized diet and increased levels of pathogenic or dysbiotic microbes [133,[274][275][276]. It is interesting to consider whether the severe inflammatory component of COVID-19 could be related to an intensified immune reaction to some of these colonizing microbes.…”

“…Another possibility involving a bacterial or fungal strain as a factor in excessive inflammation in COVID-19 was suggested recently [274]. It might be that another microbe that cross-reacts with SARS-CoV-2 is present in the alveoli or other tissues in some individuals with severe disease (L. Carrasco, UAM, personal communication).…”

Post-hunter-gatherer era microbes’ role in chronic inflammatory diseases and implications for infectious diseases

“…Diseases that have been associated with inflammation, air pollution, and a westernized diet (cardiovascular disease, diabetes, obesity, and chronic lung disease) are some of the comorbidities associated with severe COVID-19. It has been proposed that the severe inflammatory component of COVID-19 could be related to an intensified immune reaction to components of the microbiota present in various tissues [25]. These microbes might be PHM or opportunistic pathogens that take advantage of PHM-induced immune dysregulation and thus could underlie these comorbid conditions.…”