The human microbiome and COVID-19: A systematic review

Area of Science:

• Microbiology
• Immunology
• Infectious Diseases

Background:

• Human microbiotas are microbial communities symbiotic with humans.
• They influence the immune response to respiratory viral infections.
• Limited evidence exists on the human microbiome-COVID-19 relationship.

Purpose of the Study:

• To systematically review and evaluate evidence on the human microbiome and COVID-19 association.
• To summarize findings from the pandemic era.

Main Methods:

• Systematic literature review of PubMed, Embase, Cochrane Library, CINAHL, Web of Science.
• Qualitative analysis of eligible articles published up to October 31, 2020.
• Study registered with PROSPERO (CRD42020195982).

Main Results:

• 16 articles were eligible for review, analyzing stool, swab, bronchoalveolar lavage, and lung tissue samples.
• COVID-19 patients exhibited fecal microbiome dysbiosis and increased opportunistic pathogens.
• Lung microbiome dysbiosis with opportunistic pathogens was suggested in COVID-19 patients.
• The link between COVID-19 severity and the microbiome remains unclear.

Conclusions:

• The human fecal and respiratory tract microbiomes are altered in COVID-19 patients.
• Increased opportunistic pathogens are associated with these microbiome changes.
• Further research is essential to clarify the role of microbiome alterations in COVID-19 pathogenesis.