Fever after a child’s vaccination is a problem that many mothers encounter. The vaccines given to children are made of bacteria, viruses or their toxins. Although they are inactivated or attenuated, they are still some heterogeneous proteins or substances with antigenic properties, which can have certain irritating effects on the human body, and these irritations may cause symptoms such as fever and discomfort in babies. In general, they do not cause any particular discomfort, so moms and dads should not be too nervous. It is normal for a child to have a fever after a vaccination, which means it is a reaction to the vaccination, so moms and dads should not be too anxious. Because each baby is different, some will have fever and some will not have any symptoms, but fever will not affect the effect of the vaccine. It is recommended to give your child plenty of fluids after a fever appears. If the body temperature exceeds 38.5 degrees Celsius, the child can be treated with appropriate fever-reducing medication. Make sure your child rests and drinks plenty of fluids, and you can also use antipyretic patches. Ventilate the room and keep the air circulating. You can also use warm water for bathing. If the body temperature continues to rise, it is recommended to go to the hospital and ask the doctor to deal with it and give the appropriate medication. If there is still fever 2~3 days after the vaccination, there may be secondary infection and you should go to the hospital promptly.