Rubella, also called German measles or three-day measles, is a contagious viral infection best known by its distinctive red rash.
Rubella is not the same as measles (rubeola), though the two illnesses do share some characteristics, including the red rash. However, rubella is caused by a different virus than measles and is neither as infectious nor usually as severe as measles.
The measles-mumps-rubella (MMR) vaccine, usually given to children in the United States twice before they reach school age, is highly effective in preventing rubella. Because of widespread use of the vaccine, the Centers for Disease Control and Prevention (CDC) has declared rubella eliminated in the United States, but cautions parents to make sure their children are vaccinated to prevent its reemergence.