What do parents need to pay attention to after taking their children for vaccination? Generally speaking, reactions after vaccination are divided into local reactions and systemic reactions depending on the symptoms. Local reactions generally occur within 24 hours after vaccination and are mainly characterized by local redness, swelling, heat and pain in the lymph nodes around the vaccination site. Systemic reactions are relatively serious, and the most common symptoms are increased body temperature and sometimes diarrhea, nausea, vomiting, dizziness and other discomforts. I. Local reactions Local redness, swelling and pain. Some children may experience redness, swelling and pain at the vaccination site after vaccination, and this symptom usually appears within 24 hours after vaccination, which is the most common general reaction to the vaccine. The extent of redness and swelling is generally small, and only a few people have redness and swelling larger than 3 cm in diameter, which will generally subside gradually in 24 to 48 hours. Hard nodules. In some children, after vaccination with vaccines containing adsorbent, such as cell-free diphtheria vaccine, the adsorbent is not completely absorbed at the injection site, stimulating the local connective tissue to proliferate and forming hard nodules. What should I do for local reactions? First of all, for mild local reactions, i.e. redness and swelling less than 1.5 cm in diameter and hard nodules, no treatment is usually necessary. For more severe local reactions, for example, there are also some children whose redness and hard nodules will be more than 1.5 cm in diameter but less than 3 cm, then, some treatment is needed: when redness and swelling appear, you can use a clean towel to apply cold compresses first; when hard nodules appear, you can apply hot compresses. Several times a day for 10 to 15 minutes each time. A very small percentage of children will have redness and swelling larger than 3 cm in diameter and hard nodes, which is a serious local reaction. In this case, you should go to the hospital in time to deal with it. Systemic reactions A few children will have fever after vaccination and may have aversion to breast milk, lethargy, diarrhea, vomiting, etc. Some children will have skin allergic reactions such as rash and itchy skin, which are all systemic reactions after vaccination. In case of systemic reactions, when the body temperature is below 38.5℃, on the one hand, it is necessary to strengthen observation and take appropriate rest to prevent secondary diseases, and generally speaking, these reactions will disappear automatically in 1 to 2 days. When the body temperature is above 38.5℃, or even when high fever does not go away, you should take your baby to the pediatrician of the hospital in time to prevent delaying the condition.