The symptoms of virus infection are related to the type and quantity of the infected virus and the individual differences of people. Some viral infections have mild symptoms and are self-limiting, usually with mild symptoms such as low fever, rash, body discomfort and loss of appetite, etc. A small number of patients with low immunity and a large number of infected viruses can turn into more severe symptoms such as high fever and generalized rash, such as EBV infection, multiple enterovirus infections, herpes simplex virus infection, varicella-zoster virus infection etc. Some viral infections have more severe symptoms, such as the current epidemic of new coronavirus, HIV, etc. After infection, there are complications such as respiratory distress and renal failure, which can lead to death in severe cases.