Viral flu includes many viruses, including respiratory syncytial virus, rhinovirus, adenovirus, coronavirus, parainfluenza virus, influenza A virus, influenza B virus, influenza C virus, and so on. Since there are many viruses included, there are many differences in survival time. The common viral flu is basically not contagious and not very harmful, so we will only introduce the survival time of the influenza virus. The resistance of influenza virus is relatively weak and not heat resistant, and the influenza virus can be inactivated in 30 minutes at 56 degrees. Infectiousness is quickly lost at room temperature. However, it can survive for several weeks at 0 to 4 degrees Celsius, and can survive for a long time after freeze-drying below -70 degrees Celsius. The virus is sensitive to dry sunlight and ultraviolet light as well as chemicals such as ether, formaldehyde and lactic acid, which can kill it. Based on this characteristic of the influenza virus, it is known that influenza has obvious seasonality, that is, it is easy to develop in winter and spring. If you drink more water, eat more fruits and vegetables, take rest, avoid getting cold, and exercise, you will not catch a cold. In short, there are many viruses that cause the flu, and the survival time of the virus is very much related to the specific environmental virus type. Generally speaking, as long as your resistance is strong, you will not catch a cold.