Measles vaccine, the full name of which is measles and rubella diphtheria, is a biological product that prevents two diseases, measles and rubella, and does not prevent leprosy, which are three different diseases. Measles is an acute respiratory infection caused by the measles virus. Clinical symptoms include fever, cough, runny nose, conjunctival congestion, and red, grayish white dots on the oral mucosa (Koch’s spots). Rubella is an acute respiratory infection caused by rubella virus, and is also a common childhood respiratory infection, also known as wind cholera, cholera, etc. The clinical symptoms are very similar to measles and are difficult to distinguish, but the rubella rash comes and goes like a gust of wind, and the differential diagnosis is made mainly through the laboratory. And leprosy is caused by Mycobacterium leprae infection, is a chronic contact infectious disease, mainly invading the skin and peripheral nerves, serious cases can involve deep tissue and internal organs. According to the National Immunization Program, children need to be vaccinated against leprosy at the age of 8 months after birth, and in the absence of leprosy vaccine, measles vaccine can be used instead. Generally, only 1 dose of leprosy vaccine is required. Leprosy vaccine is a live attenuated vaccine that, once effective, provides lifelong immunity. Live vaccines generally require only 1 dose to be effective, but considering the organism factors and vaccine factors, it is possible that the initial vaccination may not be as effective. Therefore, a booster vaccination is required after 18 months of age. In general, measles vaccine is given in 2 doses, and the immune potency can be more than 99%. After measles vaccination, there is usually no local reaction. However, some individuals may experience a transient febrile reaction and a scattered rash within 6-12 days after vaccination. Fever after vaccination is very common and is not considered an adverse reaction to the vaccine. If the body temperature exceeds 38.5℃, you should take antipyretic drugs; if the body temperature does not exceed 38.5℃, you can use physical cooling by placing an ice pack or cold towel on your forehead, and never use antibiotics. Generally, the fever after vaccination will not exceed 48 hours, and you can go to the hospital if necessary.