Delta virus is a mutant strain of neo-coronavirus “Delta”, which is currently the predominant subtype of neo-coronavirus in the world. After infection, most patients develop symptoms within 4 days, with some patients showing symptoms within 1 day. Early symptoms usually include headache, fever, dry cough, sore throat, and malaise. A small number of patients may present with olfactory disturbances, muscle aches, nasal congestion, runny nose, diarrhea, and abdominal pain. The incubation period of individual infected patients may be longer, with reports of incubation periods of more than 20 days, while some people may not have any symptoms after being infected, so a case-by-case analysis is needed. The Delta strain has a high viral load and is more easily transmitted. After infection, the disease progresses more rapidly than the original New Crown strain, and some patients may develop symptoms such as shortness of breath, cyanosis, and respiratory distress in 3-4 days. Therefore, if you are a close contact of a confirmed NCC patient or have a history of travel to high-risk areas with symptoms such as malaise, fever, cough, and smell disturbance, you need to seek medical attention as soon as possible for nucleic acid and other tests and isolation treatment after diagnosis. Prompt vaccination against New Coronavirus, good personal hygiene protection, frequent hand washing, wearing masks, and maintaining a certain social distance are recommended to reduce the infection rate of New Coronavirus delta and other variant subtypes.