Fasting is not recommended before vaccination and there is no conflict between eating breakfast and vaccines. If the vaccine on an empty stomach may cause a series of adverse reactions, such as hypoglycemia, dizziness, etc., and may also affect the immune response of the vaccine in the body. Especially diabetic patients, fasting is easy to hypoglycemia, more should eat breakfast and then go to the vaccine. Fasting is likely to cause hypoglycemic reaction, panic, sweating, palpitations, shivering and other symptoms. When playing vaccines, a very small number of people because of nervousness can appear dizzy reaction, if there is low blood sugar, it is easier to appear a transient black eye, fainting and other symptoms, and even increase the chances of adverse reactions. In addition, the vaccine into the body to stimulate the immune response, the need for nutritional support, protein is a cytokine, antibody, complement of the main components, vitamins involved in the synthesis of immune factors, antibodies, secretion and processing work. At the same time, the immune response and daily activities will consume a certain amount of body heat, so do not fast before vaccination. Diet before and after vaccination is recommended to be nutritious, high in protein, low in fat and rich in vitamins, etc. Avoid eating too much fried, smoked and spicy food, as well as avoiding alcohol, tea and coffee. Eating a full meal is sufficient and should not be excessive, as it may cause nausea, vomiting and other discomforts. In addition, before and after the vaccine should maintain a regular routine, avoid excessive fatigue, stay up late, so as not to reduce the body’s immune response to the vaccine.