Salivary and nasopharyngeal microbial dysbiosis in COVID-19 patients. Alpha diversity of salivary (A) and nasopharyngeal (B) microbiomes of SARS-CoV-2-positive and SARS-CoV-2-negative patients. Principal coordinates analysis of weighted (C, D, left) and unweighted (C, D, right) UniFrac distances of salivary (C) and nasopharyngeal (D) microbial communities of SARS-CoV-2-positive and SARS-CoV-2-negative subjects. Statistical significance was assessed using Mann-Whitney U test for panels A and B, and using PERMANOVA for panels C and D.