Brain B and MMR vaccines can be injected together, but they should be injected at separate sites, avoiding injection on the same side. Brain B vaccine is mainly for the prevention of encephalitis B, and MMR vaccine is mainly for the prevention of measles, mumps, rubella and other diseases. The two vaccines can be injected on the same day, but attention should be paid to the injection site to avoid injecting on the same arm, and should be injected on both arms separately. If they are not given at the same time, they should be given at least four weeks apart, and it is strictly forbidden to mix the two vaccines into one syringe for vaccination. After vaccination, you should observe the vaccine for half an hour in the local medical institution before leaving, and pay attention to the cleanliness and hygiene of the skin at the injection site, avoid friction and extrusion, avoid bathing for 24 hours, and choose light ingredients for your diet. If you have any uncomfortable symptoms you should seek medical attention.