Infants with fever after MMR vaccination, for mild fever, use physical cooling, for moderate to severe fever also need to use medication. MMR vaccine is a combined live attenuated MMR vaccine, which is a triple live attenuated vaccine, and its main components: live measles, mumps and rubella viruses. Generally, a transient febrile reaction may occur within 1 to 2 weeks after vaccination. For mild febrile reaction, it can be relieved by itself after 1～2 days, and no treatment is needed; if necessary, rest appropriately, drink more boiled water, pay attention to keep warm and prevent secondary infection; For moderate fever reaction or fever time more than 48 hours, physical methods or drugs can be used to treat the symptoms. For severe febrile reaction: physical methods and drugs should be used for symptomatic treatment. To prevent febrile convulsions. Fever is a relatively common side effect of MMR vaccination in infants. The infant’s temperature needs to be closely observed and will return to normal in about 1~2 days. If the injection site has persistent fever and symptoms of redness, swelling and hot pain, it is recommended to go to the hospital in time to do routine blood tests and other infectious indicators.