If your child’s temperature does not exceed 38℃ and his/her mental state is good, he/she can be closely observed and drink plenty of fluids without any special treatment. If your child’s temperature exceeds 38℃, or if he/she is in poor spirits, lethargic, does not think of food or drink, vomits, etc., or even if the fever lasts for more than 3 days, he/she should seek medical attention from the hospital in a timely manner. Fever after the second injection of the new crown vaccine often occurs 10 to 24 hours after vaccination, mainly low-grade fever, usually lasts 1 to 2 days, most of the children’s mental state is good, it is a normal reaction to the vaccine, without special treatment. If the body temperature is greater than 38 ℃ after vaccination with the new crown vaccine, or poor mental health, lethargy, not thinking about food, vomiting and other conditions, or even fever for more than 3 days, it is necessary to consider whether it is due to other causes or infections, and it is recommended to consult the hospital in a timely manner. In conclusion, after the second injection of the new crown vaccine, most of the children fever is a normal reaction to the vaccine, parents do not need to be particularly worried, if the child continues to have a high fever for more than 3 days, or poor mental state, we should consult a doctor in a timely manner, a clear diagnosis, to take targeted treatment.