The sprayed Bacillus spores significantly inhibited the multiplications of influenza virus (417 folds), reduced bacterial co-infection concentrations (1152 folds), decreased the overreacted immune response of epithelium cells to lower IL-6 (53.9-fold), IL-8 (1.1-fold), and TNF-α (3.7-fold) pro-inflammatory cytokine levels, and increased IgA (by 1.3-fold) in nasal tract right at day 2 of treatment period. This evidence concerns the gene CXCL8 and coinfection.