The recommended age for MMR vaccination is 18~24 months old. Babies who are 18 months old can start to receive MMR vaccine, and the vaccination can be postponed in special circumstances. MMR vaccine is a combined vaccine of measles, mumps and rubella, which is mainly used to prevent measles, rubella and mumps. MMR vaccine belongs to Class I vaccine, and the national regulation of the injection time is 18~24 months of age of young children, therefore, generally 18 months old babies can start to receive MMR vaccine. Babies with acute-phase infection, fever, cough, sore throat and other symptoms need to postpone the vaccination, and it is enough to complete the vaccination before 24 months of age. After vaccination, attention should be paid to protect the vaccination site clean and dry, light diet, pay attention to rest, and avoid catching cold. The vaccine may cause localized redness, swelling, pain, hardness and other adverse reactions, and when there are adverse reactions to the vaccine, they should go to the hospital in time for timely treatment and avoid further aggravation of the condition.