There are many kinds of adverse reactions to the vaccine, including local reactions, systemic reactions, abnormal reactions of the nervous system, and rare adverse reactions, etc. The duration of each adverse reaction varies. Redness, swelling, pain and itchiness may appear at the injection site within 24 hours after diphtheria vaccine injection, while systemic reactions such as mild fever (temperature not exceeding 38℃) usually do not require treatment and may resolve on their own within 3-5 days; some children may develop hard nodules at the injection site, which are usually absorbed within 1-2 months. In addition, some children may experience transient reactions, such as benign swelling of one limb, and more rare adverse reactions such as allergic reactions, anaphylaxis, and febrile convulsions. After vaccination, children should rest properly, do not exercise strenuously, pay attention to keep warm, prevent cold or other diseases from occurring, and drink more warm water.