MMR vaccine refers to the combined live attenuated measles-mumps-rubella vaccine. Fever seven days after vaccination is generally not directly related to the vaccine, and is considered to be related to colds, pneumonia, chickenpox and other diseases. Measles mumps rubella combined live attenuated vaccine is clinically used for the prevention of measles, mumps, rubella disease vaccine. Adverse reactions to vaccination include redness and swelling at the injection site, mild fever, and transient rash. Among them, the fever reaction lasts for a short period of time and subsides quickly in a short period of time without treatment, so there is no direct relationship between fever and vaccine seven days after vaccination. For fever seven days after vaccination, it should be alerted to the fact that it is caused by colds, pneumonia, chickenpox, bronchitis caused by factors such as autoimmunity decline and pathogen infection. At the same time, you should also be alert to any other causes of fever, such as acute leukemia, lymphoma, systemic lupus erythematosus, and so on. It is recommended that those who have fever 7 days after receiving the combined live attenuated measles-mumps-rubella vaccine should consult a doctor promptly so that the cause of the fever can be clarified and treated according to the doctor’s instructions.