This article discusses the role of respiratory tract barrier dysfunction in viral-bacterial co-infections, focusing on the interaction between influenza virus and Streptococcus pneumoniae, as well as the impact of oral bacteria. It highlights how viral infections can compromise the physical and immune defenses of the respiratory tract, making individuals more susceptible to secondary bacterial infections. The article explains that viral infections can damage the airway epithelium, impair mucociliary clearance, and alter the expression of receptors that facilitate bacterial adhesion and invasion. Additionally, it discusses how oral bacteria, such as Porphyromonas gingivalis, can contribute to respiratory infections by enhancing the expression of host receptors that promote bacterial colonization. The study also explores the role of inflammatory responses in facilitating bacterial dissemination and the impact of periodontal disease on respiratory health. Overall, the article emphasizes the importance of maintaining oral health to prevent respiratory infections and highlights the need for further research into the mechanisms underlying viral-bacterial co-infections to develop effective therapeutic strategies.This article discusses the role of respiratory tract barrier dysfunction in viral-bacterial co-infections, focusing on the interaction between influenza virus and Streptococcus pneumoniae, as well as the impact of oral bacteria. It highlights how viral infections can compromise the physical and immune defenses of the respiratory tract, making individuals more susceptible to secondary bacterial infections. The article explains that viral infections can damage the airway epithelium, impair mucociliary clearance, and alter the expression of receptors that facilitate bacterial adhesion and invasion. Additionally, it discusses how oral bacteria, such as Porphyromonas gingivalis, can contribute to respiratory infections by enhancing the expression of host receptors that promote bacterial colonization. The study also explores the role of inflammatory responses in facilitating bacterial dissemination and the impact of periodontal disease on respiratory health. Overall, the article emphasizes the importance of maintaining oral health to prevent respiratory infections and highlights the need for further research into the mechanisms underlying viral-bacterial co-infections to develop effective therapeutic strategies.