In order to assess the potential of a potential anti-COVID-19 drug to reinforce the protective barrier of the mucus, epithelial lung cells like the A549 cell line 113,114 or BEAS-2B human lung cells, a human non-tumorigenic epithelial cell line 173 can be used that allow a definition of the effects of the compound on the level of mucin gene expression and mucin organization. Here, MUC5AC is linked to COVID-19.