After infection with the delta strain, the disease may develop in about 2 to 3 days, and some patients may also have no obvious symptoms. The delta strain is a mutated strain of the new coronavirus, which is characterized by a short incubation period, rapid transmission, as well as a high viral load, a long nucleic acid turnaround time, and is more likely to develop into a critical illness, among other features. Among them, because the strain is characterized by a short incubation period, the disease can develop in about 1~3 days after infection with delta virus, or even within 24 hours. Early clinical symptoms after infection with delta virus are atypical, with respiratory symptoms such as loss of taste, sore throat, and nasal congestion predominating, while severe cases may experience multiple organ failure and respiratory distress syndrome, among others. Some people infected with the Delta strain may not develop the disease and may be carriers of the virus, but they are also highly contagious and should be kept under strict isolation and observation. Symptomatic people should be treated under medical supervision.