11 months baby fever after vaccination, if less than 38.5 ℃, you can first observe and drink more water, if higher than 38.5 ℃, need to go to the hospital, if necessary, given antipyretic drugs and other treatments. 11 months baby fever after vaccination, may be a common vaccination reaction, if the body temperature is lower than 38.5 ℃, good mental state, no other discomfort, you can first observe, let the child drink more water, if necessary, to take physical cooling, such as warm towel wipe the body. If the temperature is higher than 38.5 ℃, you need to bring your child to the hospital in time, under the guidance of the doctor to use antipyretic medication, such as acetaminophen. If your baby develops persistent fever or other discomforts after vaccination, it is recommended that you take your child to the hospital for treatment under the guidance of a doctor.