Rubella, meaning “little red” in Latin, has also been referred to as German measles and third disease. It was initially believed to be a variant of measles or scarlet fever, but later determined as a separate disease in German medical reports.
A rubella epidemic in 1940 led to the discovery that rubella causes severe and devastating congenital defects, leading to the development and licensing of the first rubella vaccines in 1969. In 2005, the CDC announced that due to the success of the rubella vaccination program, rubella had been eliminated from the United States. However, outbreaks of rubella have been emerging among communities who have rejected the use of the vaccine.
Name: Rubivirus (member of the Togaviridae family)
Type of Microbe: RNA Virus
How it Causes Disease: The virus invades cells in the upper respiratory tract and spreads throughout the entire body via the lymphoid system. Systemic spread of the infection can affect many organs, including the placenta. The virus destroys cells, which leads to fetal damage and subsequent complications.
How it Spreads: Rubella is spread from person-to-person through contact with droplets dispersed in the air. The disease is contagious up to a week before and a week after the rash appears. Rubella is more common in late winter and early spring.
Who’s at Risk? All people who have not been vaccinated are at risk for infection are at risk, but the disease is generally mild for most healthy people.
However, pregnant women who get infected are at risk for spreading the disease to their fetuses, particularly if infected during the first 10 weeks of pregnancy. This can lead to severe congenital rubella syndrome (CRS), and the risk for CRS is highest if infected during the first trimester. Mothers are at risk for spontaneous abortion and premature delivery.
Pregnant women who have either been infected in the past or have received the vaccine are at low risk for reinfection (<5%) and at extremely low risk for spreading the disease to their fetuses.
Symptoms: Up to 50% of infected people show little or no symptoms. In those who do, a transient rash will develop approximately 7 to 14 days after exposure to the virus. The rash typically begins on the face and spreads downward. In general, the disease is mild, particularly in children. Adults who get infected may also develop a low grade fever, swollen glands, and cold-like symptoms. Adult women may also develop stiffness in the joints.
Infected fetuses are delayed both physically and developmentally. Physically, babies born with congenital rubella can have heart defects, mental retardation, bone alterations, vision abnormalities, and hearing loss. At birth, the baby may have a small head size, enlarged liver and spleen, inflammation in the brain, and a low platelet count (which can lead to hemorrhage).
Diagnosis: The Rubella rash itself is not sufficient for diagnosis of rubella. Laboratory tests of blood samples for antibodies against the virus are used for diagnosis. As a precautionary measure, pregnant women are routinely tested for rubella at early prenatal examinations. If rubella is suspected during pregnancy, direct tests for the virus can be done on the amniotic fluid or a small piece of the placenta removed during chorionic villous sampling (CVS).
Prognosis: For most people, the disease is generally mild with few complications. However, for pregnant women, infection of the fetus has a very poor prognosis, as the afore mentioned devastating congenital defects indicate.
Treatment: No treatment is available.
Prevention: The rubella vaccine (Meruvax-II, Merck) is very effective, leading to virtual elimination of the disease in the United States and Canada, except within communities that opt not to get vaccinated.
The rubella vaccine is a live-attenuated virus, meaning that the vaccine contains a virus that is alive, but too weak to cause disease. It is usually available as part of the MMR vaccine for measles, mumps and rubella. The vaccine is recommended for children on or just after their first birthday, with a booster prior to school entry.
Women who get vaccinated are advised to avoid pregnancy for 3 months after vaccination. Pregnant women and people who are immunocompromised (have weakened immune systems due to disease or drug therapies) should not get the vaccine.
Complications: In adults, rare complications may include encephalitis, or brain infections (1 in 6000), or long lasting joint pain in up to 70% of women. Up to 85% of babies infected during the first trimester will be born with some type of birth defect.
Sources Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases. Atkinson W, Hamborsky J, McIntyre L, Wolfe S, eds. 10th ed. 2nd printing, Washington DC: Public Health Foundation, 2008. pp. 159-174.
Rubella Disease. Immunization Action Coalition. http://www.vaccineinformation.org/rubella/qandadis.asp.
Weir E and Sider D. A refresher on rubella. CMAJ 2005; 172(13): 1680.
