The variant strain Delta belongs to a variant subtype of New Coronavirus, which has the characteristics of rapid transmission, rapid viral replication, and long time required for nucleic acid test to turn negative, etc. Symptom analysis can be done according to different periods: 1. incubation period: the incubation period of Delta infection is 4.4 days on average. However, because of the strong transmission of the virus, patients are also infectious even if they do not have symptoms of Newcastle pneumonia; 2. As the disease progresses, it may manifest as fever and dry cough, and may also be accompanied by symptoms such as itchy throat, sore throat, nasal congestion, runny nose, and diarrhea. Patients with delta infection develop into severe disease more rapidly and can develop severe manifestations such as respiratory distress and shock within a few days. Therefore, you should usually raise your awareness of self-protection, wear a mask when you go out, keep a social safety distance and avoid gathering people. Wash your hands regularly, do hand hygiene and avoid contact of unclean hands with eyes, mouth and nose. Try to keep ventilation indoors, travel safely, and avoid going to work or school with illness. If a patient has any of the above discomfort symptoms or if there are confirmed patients around, they should actively do self-protection and isolation, take the initiative to contact medical institutions for nucleic acid testing, and if the diagnosis is confirmed, isolation treatment is required.