The absence of direct contact with a patient with novel coronavirus pneumonia does not guarantee protection from novel coronavirus infection. This is because novel coronaviruses can also be contracted indirectly through contaminated objects from the patient, or through prolonged exposure in confined areas where there is a risk of aerosolized infection in a highly concentrated environment. It should be noted that contamination of the environment with feces and urine from the patient can also result in aerosol or contact transmission. Patients and asymptomatic patients with novel coronavirus pneumonia can be a source of infection, and are contagious during the incubation period, with a high degree of contagiousness within five days of the onset of the disease. So try not to go to densely populated places during the high incidence of the epidemic, and when you go out, you must wear a mask, preferably a medical surgical mask, because medical surgical masks have three layers, the outside layer is a bacteriostatic layer, and the middle layer is the isolation of the filtration layer, which can play a good protective role.