A few studies have shown that RSV infection can decrease type I IFN levels, increase IL‐17 and IL‐23 secretion, upregulate mucin gene expression (MUC5AC and GOB5), and destroy ciliated epithelial cells in COPD models, leading to mucus retention and alveolar cavity enlargement.145. This evidence concerns the gene MUC5AC and chronic obstructive pulmonary disease.