A strong reaction after a vaccination is a vaccine adverse reaction, which is caused by the characteristics of the vaccine itself and is related to the individual differences of the vaccine recipient. The vaccine itself is immunogenic, and while it induces immunity and protection against specific diseases, it may also cause some uncomfortable symptoms. If the symptoms are mild, no treatment is usually necessary; if they are severe, prompt medical attention is required. General reactions include general reactions and abnormal reactions. General reactions mainly refer to transient reactions caused by the immunogenicity of the vaccine itself, such as fever, local redness, swelling, nodules, pain, etc. Abnormal reactions refer to reactions that cause damage to tissues, organs or functions of the vaccine recipient, such as acute anaphylaxis, acute laryngeal edema, etc., which are relatively rare in clinical practice. The occurrence of adverse reactions is also related to individual factors of vaccine recipients, including allergy, abnormal immune function, mental or psychological factors, and drug effects. If local redness, swelling, pain, or hard nodules appear after vaccination, hot compresses with clean towels can be used to promote the reddening, swelling, and hard nodules to subside; if systemic allergic reactions occur, such as fever, muscle pain, dizziness, etc., they usually manifest during hospitalization and require timely treatment. If a strong reaction occurs after returning home, the situation should be reported promptly and the vaccination unit should be contacted.