Fever in children after receiving live attenuated B vaccine is a relatively common post-vaccination reaction to live attenuated vaccine. Parents should not be too alarmed, and the specific treatment depends on the degree of fever, how high the child’s temperature is, and whether other serious adverse reactions are combined. If the child only has a low fever, the temperature does not exceed 38°C, and the vaccination site is only slightly red, swollen, and painful, but there is no purulent infection, the child can continue to be observed for a period of time and drink more water and rest. If the child’s body temperature exceeds 38.5℃ and there is also severe nausea, vomiting, generalized rash, and even angioedema and anaphylactic shock, go to the pediatric department of the local hospital for anti-allergic treatment as soon as possible.