The investigators plan to carry out an experimental study on the preventive effect of recombinant human interferon alpha nasal drops on the infection of 2019 new coronavirus in medical staff.

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.