Delta virus is very contagious and mutates quickly, and can develop in 24 hours, and there are no typical clinical symptoms after infection, no difference with the symptoms of previous new coronavirus infection, a significant proportion of patients are asymptomatic infected, but compared with previous new coronavirus is more likely to develop into serious illness. Prevention and control of this virus is very important and can be done from personal protection: 1, actively vaccinated against the new coronavirus: vaccination is an effective measure to prevent the disease, and the rate of infection in the vaccinated population and the incidence of severe disease after infection are significantly lower than those who are not vaccinated; 2, go out and do self-protection: properly wear a mask to prevent respiratory droplet transmission. The hands are fully exposed parts of the body and are more likely to come into contact with bacteria and viruses, so pay attention to thorough hand washing and diligent cleaning to reduce the incidence of infection; 3. Try not to visit or accompany people in the hospital, if you must accompany them, you should take the initiative to do nucleic acid testing, and string wards, slip corridors, and gather to chat are strictly prohibited. 4. Avoid going to medium and high-risk areas: With the application of big data in epidemic prevention and control, major media will report on medium and high-risk areas in the country every day, and at the same time, local epidemic prevention and control commands will increase the control of medium and high-risk areas, so the general public should pay attention to the announced Medium and high risk areas and avoid going there. Try not to go out during special periods; 5. Take the initiative to seek medical attention: If you have been in contact with an infected person or have visited places where cases have occurred and find yourself with fever, mild sore throat, fatigue and weakness as well as gastrointestinal discomfort such as nausea and diarrhea, or if your sense of smell or taste becomes impaired, you need to take the initiative to seek medical examination to avoid delaying treatment.