Neocoronavirus pneumonia is a condition that can present with yellow sputum as well as white sputum. There is no clear correlation between the color of sputum and neocoronavirus pneumonia. In general, it is not possible to determine whether or not you are infected with neocoronavirus pneumonia by the color of the sputum. When an infection occurs in the respiratory tract (commonly viral, rarely bacterial, etc.), sputum is produced because of a localized inflammatory response that increases mucus secretion from the epithelium of the respiratory tract. Viral or bacterial infections also produce yellowish-green sputum because the respiratory epithelium secretes a large number of polymorphonuclear leukocytes and polymorphonuclear leukocyte enzymes which are yellow or green in color, so the sputum may appear yellowish-green. We cannot distinguish the cause of infection by the color of sputum, nor can we distinguish the type of infection. If you have a cough and sputum and suspect that you are infected with neocoronavirus pneumonia, it is recommended to improve the nucleic acid test of neocoronavirus for further clarification.