There is no clear rule on the latest time for infants to receive MMR vaccine. The generally recommended early timing is for infants to receive the 1st dose at 18 months, the 2nd dose at 1.5 years of age, and a booster dose at 6 years of age. If the infant has fever or cold, the vaccination can be given after the condition has improved. If the infant has some underlying diseases, such as epilepsy or particularly low immune function, MMR vaccination is not suitable and can be given after the infant’s epilepsy is well controlled and immune function is basically normal. If infants did not receive MMR vaccine in the early years, they can also be revaccinated at 4-6 years of age. When receiving MMR vaccine, it is important to be in good health. Because the immune function is relatively low during the illness, if the leprosy vaccine is inoculated it will aggravate the adverse reaction of the leprosy vaccine and also aggravate the condition.