Viral colds are more contagious in the 1-3 days of the disease. As the treatment progresses and the symptoms improve, the virus of the cold will be gradually discharged from the body, and the viral cold will be relieved in about 1 week, that is, the contagiousness of patients with common colds caused by viral infections will disappear in about 1 week. Influenza A, influenza B and other influenza viruses cause colds, often the disease itself is more serious and there may be a contagious period of about 2 weeks. No matter what kind of cold patients have, in order to prevent cross-infection to do a good job of respiratory isolation, keep indoor ventilation, disinfection, try not to go to crowded places, usually also drink more water, more rest, to prevent being infected with the flu.