Delta is a mutated strain of the new coronavirus, which has a short incubation period, strong infectiousness, rapid onset and great difficulty in treatment. After human infection with delta, most patients have latent infection and mild infection, but a small number of patients can develop serious illness as early as 3-4 days, and serious cases can turn into severe or even critical illness within 24 hours, at which time they need to enter the intensive care unit for treatment. After the onset of Delta infection, the early symptoms may only be drowsiness, weakness, abnormal sense of smell, or mild muscle aches and pains, etc. With the development of the disease, symptoms such as red eyes, sore throat, nasal congestion, runny nose, abdominal pain, diarrhea, and red rash may appear. If the patient has a chronic disease or poor health, or if the disease is not treated in time, it is likely to develop into a severe disease, which may manifest as respiratory distress, cyanosis, hypoxemia, etc., and may even lead to shock, metabolic acidosis, and multi-organ failure. Therefore, people with symptoms such as drowsiness, weakness, abnormal sense of smell, and mild muscle aches, especially those with a history of travel to high-risk areas or close contact with confirmed patients, must seek medical attention for nucleic acid testing, and those who are diagnosed need to be treated in isolation to avoid deterioration of the disease and affect the prognosis. At the same time, protective measures should be taken during medical visits to avoid transmission to others. Vaccination with the new crown vaccine has a certain protective effect on delta, so it is recommended that people who are eligible for vaccination should be actively vaccinated. You should also pay attention to personal protection in your daily life, wear masks properly, keep a safe distance, wash your hands and disinfect regularly, and go to less crowded places to prevent delta infection.