Measles is a high fever that lasts 3 to 5 days and the fever goes down and the rash comes out, while the reaction to MMR vaccination is a low-grade fever that returns to normal in about 3 days. Measles in toddlers is a high fever lasting 3 to 5 days, with a temperature of 39℃ or even more, and no other symptoms, until the rash appears, the fever will not go down, which is often referred to as the fever goes down and the rash comes out. The order of rash in toddlers is generally from the hairline, behind the ears, the face until the chest and back, the rash is all over within 24 hours, and then begin to subside, after the rash subsides, there is no pigmentation of the skin or peeling phenomenon. If a high fever persists, it is recommended to go to the hospital for treatment. After receiving MMR vaccination, there are usually some reactions, such as fever, nausea, loss of appetite, redness, swelling, pain and hardness at the vaccination site, etc., which will usually be relieved by themselves in about 3 days, and the fever temperature is low, usually lower than 38.5℃. If a rash occurs, it is often not sequentially related to the fever. Whether adverse reactions occur varies from person to person, and some vaccinees do not have them. After vaccination, it is recommended to drink plenty of water to promote metabolism, do not bathe for two days, and do not eat seafood, fish and shrimp.