Pneumonia is not usually contagious. The disease occurs mainly in the lower respiratory tract and is less contagious, and young adults who are healthy and have strong immune systems are less likely to be infected. However, people with low immunity can contract pneumonia through saliva transmission. It is recommended to avoid contact with pneumonia patients and to take protective measures. Special types of pneumonia, such as mycoplasma pneumonia, are contagious and can be spread on a small scale in groups of young children or families.