The causative agent of novel coronavirus pneumonia is a novel coronavirus. With the understanding of the novel coronavirus, it has been found that after infection with the novel coronavirus, the process between infection and onset of illness is called the incubation period, which can range from 1-14 days. In some patients, the onset of illness may occur within 1-2 days of infection and may be characterized by cough, fever, and chest tightness and shortness of breath. Some people may have a longer incubation period and develop the disease after 2 weeks. Others may have a longer incubation period, up to 20 days. Therefore, at present, the incubation period of novel coronavirus pneumonia is usually considered to be around 2 weeks, and may be more than 20 days in some patients. Source: Dr. Yurai