The investigators plan to carry out an experimental study enrolling more than 2000 medical staff and divide participants into low-risk group and high-risk group according to whether they can directly exposed to 2019-nCOV infected patients. In the low-risk group, participants will be given recombinant human interferon alpha-1b nasal drops (2-3 drops/nostril/ time, 4 times/ day), and in the high-risk group will be given preventive intervention with interferon nasal drops and thymosin-α (thymosin was injected subcutaneously once / week), and the intervention time is 28 days.
