The precautions and contraindications after the third vaccination are to stay in the observation area for 30 minutes, keep the vaccination site dry and clean, and pay attention to diet. 1. After receiving the third dose of the new crown vaccine, you need to wait in the observation area for 30 minutes to make sure there are no symptoms of discomfort before leaving, so as to avoid any adverse reactions from the body and not receive timely treatment. 2. After the third vaccination, try not to take a shower, the vaccination site should not be wet for 24 hours, and should not do strenuous exercise, so as to avoid the body sweating a lot. It is important to keep the vaccination site clean and hygienic to avoid infection at the vaccination site. 3. After the third vaccination, avoid eating spicy, stimulating, cold and beans, seafood and other allergy-prone foods for one week, and try not to drink alcohol, so as not to induce an adverse reaction to the vaccine. In addition, pay attention to rest, avoid overwork, and develop good habits.