Localized redness and swelling of infants after vaccination can be treated with observation therapy, general treatment or medical treatment according to the condition. 1. Observation therapy: Redness and swelling may appear locally after vaccination, which is also an adverse reaction. If the diameter of redness and swelling is less than 1.5 cm, and the infant does not accompany other symptoms, there is no need for special treatment, parents can pay attention to observe the local skin, and most of them will disappear after a period of time. 2. General treatment: If the diameter of local redness and swelling after vaccination ranges from 1.5 to 3 centimeters, parents can use a towel wrapped in ice packs to apply ice at an early stage, and local hot compresses at a later stage, which can help to alleviate the phenomenon of redness and swelling. 3. Medical treatment: If the diameter of the local redness and swelling is more than 3 cm or the infant accompanied by other uncomfortable symptoms, we should be alert to the allergic reaction or other factors caused by an abnormal phenomenon, the need to consult a doctor in a timely manner. If it is clear that it is caused by allergy, if necessary, follow the doctor’s instructions with antihistamines, such as chlorpheniramine, loratadine and so on. Parents are advised to take appropriate measures according to the actual situation of their babies, and should also seek timely medical treatment to avoid accidents. After vaccination, parents should strengthen the skin care of the injection site of infants to avoid foreign body friction and irritation.