Measles vaccine, full name is combined measles and rubella vaccine. Measles and rubella are both respiratory infections caused by viruses, and the use of live measles and rubella diphtheria vaccine can effectively prevent the occurrence of both of these infections. Leprosy vaccine is a Class I vaccine, which is required to be given to children under the National Immunization Program. After receiving this vaccine, the body is stimulated to develop immunity against measles and rubella viruses. When should the leprosy vaccine be given? According to our regulations, children ≥ 8 months of age are generally eligible for vaccination. It is important to note that the contraindications to leprosy vaccination should not be ignored. Because babies have a low immunity, they can easily catch a cold or have a fever due to other diseases. The leprosy vaccination at this time can aggravate the baby’s condition or induce complications, and can also raise the body temperature. Babies should not be vaccinated when they are recovering from an infectious disease or have a history of exposure to an acute infectious disease, but have not yet passed the quarantine period. If the vaccine is administered at this time, there is a high risk of adverse reactions or aggravation of the original condition. Such people can postpone the leprosy vaccination until the disease has improved. Usually babies have a vaccination book, and after each visit, the doctor will inform the type and time of the next vaccination accordingly, and parents can make their own decisions based on this information. If the child is sick on the day of the vaccination, the vaccination can be postponed, but preferably not for more than a week, as all vaccinations will be postponed for too long, which is not good for the prevention of certain diseases. Leprosy vaccination has a higher success rate when the baby is 8 months old. If a baby is contraindicated for leprosy vaccination due to illness or other reasons, the vaccination can be delayed, but if he or she returns to a state where he or she is eligible for the vaccination, he or she should get it in time. Finally, how many times should the leprosy vaccine be given? Generally speaking, the leprosy vaccine should be given only once, and once the vaccination is effective, you will be immunized for life. However, considering the factors of the body and the vaccine, it is likely that the initial vaccination will be ineffective. Therefore, it is necessary to give a booster vaccination after 18 months of age.