After vaccination, redness, swelling, itching, pain and hard nodules may appear at the injection site, and symptoms such as low fever, fatigue, muscle pain, loss of appetite, dizziness, vomiting and slight rash may also occur, which are usually normal. It is usually normal. Drinking plenty of water and taking rest are sufficient for daily use, and no special treatment is necessary. Very few patients may develop symptoms such as high fever, vomiting, persistent irritability, drowsiness, cold extremities, mental discomfort, syncope, hematuria, allergic rash, allergic purpura, angioneurotic edema, etc. after vaccination. It is recommended to go to the hospital promptly and conduct relevant examinations to exclude the presence of other complications and actively carry out treatment. In case of convulsions, breathing difficulties, or even serious symptoms such as anaphylaxis or toxic shock, immediate resuscitation measures and prompt medical attention are required. The above side effects after vaccination may be caused by various reasons, such as the composition of the vaccine and the body type of the vaccine recipient. In addition, vaccines are foreign substances that enter the body and may cause some minor side effects. It is recommended that the general public be aware of the indications and contraindications before vaccination and pay attention to their own conditions. If there are symptoms such as inflammation, fever, diarrhea, etc., vaccination is not recommended to avoid aggravation of symptoms or other side effects. For people with allergies, they should also have their allergies assessed by a professional doctor before vaccination to clarify whether the vaccination is appropriate.