The MMR vaccine is a hybrid vaccine used to prevent three infectious diseases, including measles, mumps, and Rubella. The vaccine is usually administered in two doses in childhood.<br> < br>1) measles: a viral disease that causes fever, cough, skin rashes, and respiratory problems and can cause serious complications such as pneumonia, brain inflammation, and even death.<br>2) mumps: a viral disease that causes swelling of the salivary glands and can lead to complications such as inflammation of the testicles in men and inflammation of the ovaries in women.< br>3) rubella: a viral disease that for adults usually has mild symptoms, but can damage the fetus during pregnancy, causing birth defects such as blindness and heart defects.<br><br>This vaccine is usually given to children at the age of 12 months and again at the age of 4-6 years. The MMR vaccine is widely prescribed in many countries to prevent these diseases and is usually safe and effective.