Respiratory infection

Respiratory infections (RTIs) can affect any part of the body involved in breathing, from the nose and throat down to the airways and lungs. RTIs are divided into two categories: upper and lower. Adults get between two and three upper RTIs, such as the common cold, per year. Children, especially young children, may experience more because their immune system is still developing. Lower RTIs, such as pneumonia, tend to be more serious than upper RTIs.