Adverse reactions are reactions caused by the characteristics of the vaccine itself, which are not related to the purpose of vaccination or unexpected, including general reactions and abnormal reactions, while general reactions mainly refer to the transient reactions caused by the inherent characteristics of the vaccine itself, and abnormal reactions mainly refer to those that cause damage to the tissues, organs or functions of the vaccine recipient. The general reactions mainly refer to the one-off reactions caused by the inherent characteristics of the vaccine itself, while the abnormal reactions mainly refer to the adverse reactions that cause damage to the tissues, organs or functions of the vaccine recipient and occur rarely, such as acute severe allergic reactions. General reactions mainly include fever, local redness, swelling, hard nodules, weakness, nausea, headache, muscle pain, etc. These symptoms are all transient and mild reactions of the body, which can disappear within 2-3 days with rest and a light diet, so there is no need to worry. As for hypersensitivity reactions that may occur in a very small number of people, they usually occur immediately after vaccination, so it is necessary to stay for 30 minutes after vaccination, and once a serious allergic reaction occurs within 30 minutes, there will be professional staff to carry out rescue measures. Adverse reactions after vaccination usually vary from person to person and are unavoidable. Because vaccines induce the human immune system to produce protection against specific diseases, they may also cause adverse reactions in a small number of vaccinees due to their biological characteristics. Therefore, it is recommended that vaccinees take rest before and after vaccination, and try not to smoke, drink alcohol, or eat spicy and stimulating foods to reduce the probability of adverse reactions. If a vaccinator suspects an abnormal reaction (e.g. allergic symptoms) in the body after vaccination, he or she needs to go to the hospital for consultation and treatment, and consult and report to the vaccination clinic, medical institution or CDC. For those who need investigation, diagnosis or identification, the vaccinees should provide relevant information such as past medical history and medical records of the visit as required and cooperate with the follow-up related work.