Truly asymptomatic infected individuals who have been free of disease generally do not have sequelae. The infected person will not know that he or she is infected if he or she does not undergo pathogenic examination, because there are no symptoms and no tissue or organ damage, so there will be no sequelae. Some patients with transient asymptomatic infections are in the incubation period of the infection and have not yet developed symptoms, but will start to show clinical symptoms after some days. Some patients have typical clinical manifestations, some patients have atypical clinical symptoms, only fatigue, headache, muscle pain and other non-specific manifestations, some patients with atypical symptoms may last for a long time before gradually remitting, generally will not leave sequelae. Patients with typical symptoms may also have symptoms that last for a longer period of time. These symptoms will gradually remit and disappear later and are not strictly considered sequelae because they can gradually get better with time. The sequelae are usually not completely recovered after a long period of time, for example, in patients with novel coronavirus infection, in case of severe pneumonia, some patients may be cured and left with different degrees of pulmonary fibrosis, and pulmonary fibrosis is a sequelae.