Rubella virus is the only member of the genus of Rubivirus and belongs to the family of Togaviridae. In young children, rubella is usually mild. They may have a fever and a sore throat. Adults are more likely to have a headache, pink eye, general discomfort, and rash. Adults also tend to have more complications, including sore, swollen joints and, less commonly, arthritis, especially in women. Encephalitis is a rare but serious complication that can affect adults with rubella. However, the most serious consequence from rubella infection is the harm it can cause a pregnant woman’s baby.