Screening for Rubella Health Article

What Do I Have?

Rubella (also called German measles, or 3-day measles) is an infection caused by an RNA virus. Only one strain of the virus exists. Rubella occurs primarily in young children and adolescents, and is most common in the springtime. Major epidemics of rubella occurred in the in 1935 and 1964; minor sporadic epidemics occurred approximately every seven years until the late-1960s. After an effective vaccine was licensed in 1969, the frequency of rubella declined nearly 99%. Today, rubella is rare and primarily occurs in people who have not received the vaccine.

How Is Rubella Transmitted?

Rubella is spread through respiratory droplets (coughing and sneezing) and enters your body as you breathe it in through your mouth or nose. From there, the virus travels quickly to the lymph nodes in the neck and is spread by the bloodstream throughout the body. The incubation period is approximately two to three weeks; that is, it takes that long after the virus enters your body for the infection to develop. The virus is present in blood and in the secretions from the nose and throat for several days before the characteristic rash appears. Once the rash appears, the virus will "shed" from the nose and throat for several days. You are, therefore, contagious for an extended period of time.

What Are the Signs and Symptoms of Rubella?

The principal symptom of rubella is a widespread red rash with small bumps. The rash typically begins on the face and torso before spreading over the body. Unlike chickenpox, the rubella rash does not itch. Mild symptoms, such as malaise (not feeling well), headaches, muscle aches (myalgias), and aches in the joints (arthralgias), typically accompany this condition, as well as swollen lymph nodes behind the ears and a mild eye infection (conjunctivitis, or pink eye). These symptoms usually disappear within three to five days.

Other conditions that may produce symptoms similar to those of rubella include rubeola, roseola, other viral rashes, and drug reactions.

What Are the Consequences of Rubella Infection in Pregnancy?

Rubella rarely poses a serious problem for the pregnant mother. However, when infection occurs in the first trimester of pregnancy, it can put the fetus in serious danger. This is because the rubella virus crosses the placenta through the bloodstream. The longer a baby is exposed to the virus, the more likely it is that the baby will become infected.

• Approximately 50% of babies exposed to rubella within four weeks of conception will develop signs of congenital infection.
• When maternal infection occurs between the 4th and 8th week of pregnancy, approximately 25% of babies will be infected.
• When infection develops in the third month, (eight to 12 weeks) approximately 10% of babies will be infected.

When maternal infection occurs beyond this point in time, less than 1% of babies will be infected.

Babies who are infected with rubella while in the uterus are susceptible to serious birth defects. The four most common defects are:

• deafness (affecting 60 to 75% of infected infants);
• eye defects (10 to 30%);
• abnormalities of the brain (10 to 25%); and
• cardiac malformations (10to 20%), such as narrowing of the pulmonary artery.

Other possible defects include restricted growth in the uterus, mental retardation due to an abnormally small brain, pneumonia, enlargement of the liver and spleen, and depressed blood counts. Approximately one-half of all children infected in the womb will later attend schools for the hearing impaired, and only 25% are able to attend mainstream schools. Some children will develop insulin-dependent diabetes later in life.

How Is Rubella Diagnosed?

If you have rubella, your doctor may be able to tell just from a physical examination. If necessary, your doctor will order blood tests to detect antibody to the virus. (Antibodies are produced by your immune system to combat specific infectious agents that have entered your body.) The antibody against rubella does not normally appear in your blood until after the rash has developed. IgM antibody-the initial form, produced after your immune system detects the pathogen-usually reaches a peak seven to 10 days after the onset of illness, then declines over the next four weeks. The serum concentration of IgG antibody-the later form-typically rises more slowly, but its level will then persist throughout your lifetime.

Can Rubella Be Prevented?

Approximately 95% of patients who receive the rubella vaccine become immune to infection, and the vast majority of these individuals remain immune for life. A small number of patients will lose their immunity as they age and require revaccination. Ninety percent of people who receive the vaccine have the antibodies for 18 years. Rarely, second infections have occurred after both natural, primary infection and vaccination. However, recurrent infections generally are not associated with serious illness, viremia (the presence of virus in the bloodstream), or fetal infection.

Rubella was widespread until a vaccination became available in 1969. Vaccines contain a small amount of the infectious agent-not enough to make you sick, but enough to mobilize your immune system to produce antibodies specific to that agent. Immunity to rubella is usually permanent. Once you have had the disease or have been vaccinated, your antibodies against the virus will protect you against infection for life.

Vaccination Prior to Conception

Ideally, if you are planning a pregnancy, you should see your doctor before conception. At this time, you will be evaluated for immunity to rubella. If serologic testing, which can detect the presence of antibodies in the blood, shows you to be susceptible, you will receive a rubella vaccination.

Prenatal Testing

If you have not seen your doctor for preconception counseling, you should be tested for rubella during your first prenatal appointment. If you are susceptible to rubella, you and your doctor will discuss how to avoid exposing others. Your doctor will also retest you later in pregnancy if you develop symptoms or signs of rubella. If you are infected then, your doctor will conduct diagnostic tests (ultrasound) to see if your baby is also infected. Because of the risk of serious fetal abnormalities due to rubella, you and your doctor may also discuss the option of terminating the pregnancy.

Postpartum Vaccination

If you are susceptible but do not actually get infected during pregnancy, you should be vaccinated immediately after giving birth.

The present rubella vaccine is the RA 27/3 vaccine. It is available in a monovalent form (only effective against rubella), bivalent form (effective against measles and rubella, known as MR) and trivalent form (effective against measles, mumps, and rubella, known as MMR). In addition, the vaccine can be administered with other immune globulin preparations, such as rH-immune globulin.

Women who receive the vaccine cannot transmit infection to others. It is safe for mothers who are breast-feeding to be vaccinated.

Side Effects

There are a few potential adverse effects of vaccination, even in adults. Less than 25% of patients develop mild symptoms, such as low-grade fever and malaise. Less than 10% experience achy joints, and less than 1% develop arthritis (inflammation of the joints).

Preventing Pregnancy Soon After Vaccination

Women who receive the rubella vaccine should use secure contraception (birth control pills) for at least three months after vaccination. For a number of years, the Centers for Disease Control and Prevention (CDC) maintained a registry of women who received the rubella vaccine within three months of conception. Among almost 400 patients identified, there were no instances in which congenital rubella syndrome resulted from vaccination. But, theoretically, there still may be a 1 to 2% risk of congenital rubella due to the rubella vaccine in early pregnancy.

For information about other infections screened early in pregnancy, go to Toxoplasmosis in Pregnancy, Screening for Parvovirus in Pregnancy, CMV in Pregnancy, Screening for HIV in Pregnancy, Varicella, Syphilis in Pregnancy, Listeria, and Hepatitis in Pregnancy.