Rubella is a contagious, generally mild viral infection that occurs most often in children and young adults. Here's more on the disease.
 

While rubella virus infection usually causes a mild fever and rash illness in children and adults, infection during pregnancy, especially during the first trimester, can result in miscarriage, fetal death, stillbirth, or infants with congenital malformations, known as congenital rubella syndrome (CRS).

The rubella virus is transmitted by airborne droplets when infected people sneeze or cough. Humans are the only known host. In children, the disease is usually mild, with symptoms including a rash, low fever (< 39°C), nausea and mild conjunctivitis. The rash, which occurs in 50–80 per cent of cases, usually starts on the face and neck before progressing down the body, and lasts 1–3 days.

Swollen lymph glands behind the ears and in the neck are the most characteristic clinical feature. Infected adults, more commonly women, may develop arthritis and painful joints that usually last from 3–10 days. Once a person is infected, the virus spreads throughout the body in about 5-7 days. Symptoms usually appear 2 to 3 weeks after exposure. The most infectious period is usually 1–5 days after the appearance of the rash.

When a woman is infected with the rubella virus early in pregnancy, she has a 90 nper ce chance of passing the virus on to her fetus. This can cause miscarriage, stillbirth or severe birth defects known as CRS. Infants with CRS may excrete the virus for a year or more.
Children with CRS can suffer hearing impairments, eye and heart defects and other lifelong disabilities, including autism, diabetes mellitus and thyroid dysfunction – many of which require costly therapy, surgeries and other expensive care.