Lung infections are contagious, especially in elderly people with severe coughs and phlegm, and children who are picky eaters and have poor body resistance can be easily infected by the elderly. If there are elderly people and children at home, it is recommended to open windows and ventilate frequently. If an elderly person develops a cough and fever, it is recommended to seek medical attention and not to share a room with a child. If an elderly person develops a lung infection, it is usually spread by coughing, coughing up sputum, and droplets of pathogenic bacteria that lurk in the air they breathe.