If the fever is not going down after the vaccination, it can be caused by the adverse reaction of the vaccine, which can be treated by physical cooling and oral antipyretic. You can use warm towels to wipe the groin, armpits, head and neck, or use antipyretic patches to lower the temperature physically. You can also drink more water at the same time to facilitate sweating and cooling to achieve relief of high fever. If the fever exceeds 38.5 degrees, the patient can be treated with fever-reducing medications, such as ibuprofen and acetaminophen, etc. Parents should be careful not to use antibiotics or hormone medications during this period. When the patient has been playing the B brain vaccine appeared to have been high fever does not go away phenomenon, you need to consult a doctor in time. And under the guidance of the doctor to take drugs to avoid the risk of medication.