MMR stands for measles, mumps, and rubella, which are three viral infections that can be prevented through vaccination. Here’s an overview of the MMR vaccine and the diseases it protects against:

1. Measles: Measles is a highly contagious viral infection characterized by fever, cough, runny nose, and a characteristic rash that typically starts on the face and spreads to the rest of the body. It can lead to complications such as pneumonia, encephalitis (brain inflammation), and death, especially in young children and immunocompromised individuals.
2. Mumps: Mumps is a viral infection that causes swelling of the salivary glands, resulting in a characteristic “chipmunk-like” appearance. Other symptoms include fever, headache, muscle aches, and fatigue. Complications can include inflammation of the testicles (orchitis), ovaries (oophoritis), pancreas (pancreatitis), and meningitis.
3. Rubella (German measles): Rubella is a viral infection that typically causes a mild illness with a rash and low-grade fever. However, if a pregnant woman contracts rubella, especially during the first trimester, it can lead to serious birth defects in the baby, known as congenital rubella syndrome.