Coronaviruses are highly infectious throughout the incubation and onset periods, with most being more contagious within 1-2 weeks of onset. However, there is some individual variability due to different body types, different types of coronaviruses, and different treatment status. Coronaviruses are named for the spine-shaped bumps on the envelope of the virus that resemble a crown. Coronaviruses infect only vertebrates, such as humans, cats, rats, dogs, and birds, and can cause respiratory infections mainly in humans. The common ones are SARS-CoV virus, HCoV-OC43 virus, MERS-CoV virus, and the well-known new coronavirus. These viruses are mainly transmitted through breathing and saliva, and can enter the respiratory system through the nose and mouth and cause damage to the trachea, bronchi and lungs. When a person is infected with a coronavirus, the viral load in the patient’s body is usually high at the beginning of the illness, i.e. 1-2 weeks, when the infection is more contagious. As treatment progresses, the viral load decreases and infectivity decreases. When a person is infected with a coronavirus, such as a novel coronavirus, it is highly contagious throughout the incubation period and the onset of the disease, and the symptoms are similar to those of the common cold, such as fever and dry cough. Therefore, when a patient develops these uncomfortable symptoms, especially those who have recently visited a high-risk area, they need to immediately report to the community and hospital and undergo isolation, diagnosis and treatment to avoid serious consequences.