Fever means fever, and the vaccine should not be given when you have a fever. Fever is a contraindication to the New Crown vaccine and it is recommended to wait until the body temperature returns to normal before administering the New Crown vaccine. The following adverse effects can occur when you have a fever: 1. confusion or masking of adverse reactions: since adverse reactions such as fever and malaise may also occur after vaccination, vaccination when you have a fever may confuse or mask the adverse reactions of the vaccine, which is not conducive to the timely detection and treatment of adverse reactions; 2. inducing or aggravating adverse reactions: when you have a fever, the body is usually in the process of a certain disease and the immune function of the body is not optimal. If the vaccine is administered at this time, the immunogenicity of the vaccine will stimulate the organism, which will easily induce or aggravate adverse reactions such as dizziness, headache, weakness and diarrhea; 3. Interference with the effect of the vaccine: fever is an adaptive defense response shown by the organism when attacked by a disease, which is an immune response, and the effect of the new crown vaccine in the organism also depends on the immune response. Therefore, the vaccination should be suspended in case of fever. Other situations where vaccination should be withheld include acute attacks of gout, severe colds, heart attacks, brain attacks, and patients with malignant tumors before or after surgery or during chemotherapy or radiation therapy. For people with symptoms such as headache, dizziness, nausea, vomiting, chest tightness and stomach discomfort, the cause should be identified and medical advice should be followed to decide whether or not to vaccinate. In addition, people with urticaria and acute diarrhea are not suitable for vaccination. For details, consult your local vaccination medical staff and follow professional advice. In addition, you should take rest before vaccination, avoid strenuous exercise, maintain regular rest and rest, ensure sufficient sleep, and avoid spicy and irritating foods and foods that may cause allergic reactions such as seafood. Pay attention to the cleanliness and dryness of the vaccination site and keep your mood relaxed.