Most of the vaccinees will basically not have adverse reactions after vaccination, but there are very few vaccinees who will have strong uncomfortable symptoms, such as local sterile abscess, high fever fainting, anaphylaxis, laryngeal edema, convulsions, etc. At this time, you should contact the vaccination site or go to the nearest hospital to clarify the cause of occurrence so as not to delay treatment. However, most of the vaccinators who had adverse reactions had transient adverse reactions, and the main symptoms were as follows: 1. Systemic reactions: such as mild fever, dizziness, headache, malaise, muscle pain, etc. Generally, the uncomfortable symptoms can disappear in 1-2 days after vaccination. However, when the fever is >37.5℃ or accompanied by other systemic symptoms, such as abnormal crying of children, it is necessary to seek medical attention promptly; 2. Gastrointestinal symptoms: such as nausea, vomiting, abdominal pain, diarrhea, etc. If the symptoms continue to progress or are more serious, it is necessary to seek medical attention for diagnosis; 3. Skin symptoms: the discomfort reactions such as local hard nodules, itching, redness, swelling and pain are common in vaccination, and generally disappear gradually after 1-2 days. If the diameter of redness and swelling and hard nodules are <1.5cm, generally no treatment is needed; if the diameter of redness and swelling and hard nodules are 1.5-3cm, local cold compresses can be applied and changed to hot compresses when only hard nodules are present until they dissipate; if the diameter of redness and swelling and hard nodules are ≥3cm, prompt medical consultation is required. However, it should be noted that the local redness and swelling after BCG vaccination should not be applied with hot compresses.