FIGURE 3.

The potential causal relationship and processes between severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) and gut microbiota alterations. SARS‐CoV‐2 recognizes the angiotensin‐converting enzyme 2 (ACE2) receptor in the intestinal epithelium through S protein and triggers abnormal immune responses, such as activation of CD8+ T cells. The immune microenvironment interacts with microbiota alterations, which is accompanied by changes in short‐chain fatty acid (SCFA) metabolites. These metabolites may regulate the immune response, S protein activity, and ACE2 receptor expression.