Nine-month-old babies with fever after MMR vaccination, if there is no other abnormal manifestations can continue to observe and reasonable fever, such as mental depression or temperature recurrence obvious, need to consult a doctor to clarify whether the disease state. Nine-month-old babies with fever after MMR vaccination, may be a post-vaccination reaction, generally manifested as a low fever, and a shorter duration, the recurrence is not obvious, the spirit is still good, and there are no other abnormal symptoms. This kind of children can be observed first, and carry out reasonable symptomatic fever reduction, such as the use of warm water wipes and other physical cooling, if the temperature exceeds 38.5 ℃ can be used to acetaminophen and other drugs to symptomatic fever reduction. For babies with recurring temperature, high fever, prolonged fever, or depression with other abnormal symptoms, it is recommended to consult a doctor to identify whether the baby is in a state of illness, rather than a post-vaccination reaction. A specialist should evaluate the baby for a definitive diagnosis and treatment, such as oseltamivir phosphate granules for upper respiratory tract infections caused by influenza virus. If your baby’s fever is not relieved, or is accompanied by other symptoms, you should go to the hospital for treatment to identify the cause. All of the above medications should be used under the guidance of a doctor, avoid self-medication.