The cause of the epidemic. As of June 5438+February 65438+June, 2022, according to the Tsinghua University epidemic documents, Tsinghua University is a low-risk area, and Tsinghua University is closed due to the epidemic. In order to ensure the safety of people in this area, it is necessary to carry out 24-hour nucleic acid testing to prove that it is necessary to go in and out. At the same time, we must pay attention to personal protective measures and avoid going to crowded places.