Rubella

September 26, 2011

Rubella is commonly referred to as German measles or 3-day measles. This disease is a common and relatively mild disease of childhood. The disease is caused by an RNA virus (genus: Rubivirus, family: Togaviridae) and humans are the only known host. Rubella is passed by secretions; nasopharyngeal, blood, stool, or urine. The virus can be recovered from secretions 7 days before symptoms start and up to 7 days after the rash disappears. The incubation period is 14-21 days and usually 16-18 days. Rubella outbreaks often occur in late winter and early spring. Outbreaks, which have occurred since the vaccine development, are usually in environments where close contact with other individuals occurs such as dormitories or health care environments.

CLINICAL COURSE

Rubella, in postnatal infection, begins with swollen lymph nodes in the head and neck regions, in particular, the occipital lymph nodes. Within 5 days, a mild enanthem of rose-colored spots may be noted on the soft palate. Sore throat, conjunctivitis, and enlarged spleen are the next symptoms, followed by fever, usually low grade (< 38.5°C; 101oF), and rash. The rash begins in the face and then proceeds to the trunk and extremities. The rash has discrete maculopapular (raised but flat) and slightly erythematous (red) lesions that last about 3 days. Other symptoms that may occur are anorexia, headache, and malaise. Less common symptoms include polyarthritis, usually of small joints of hands and feet among women, and paresthesias (abnormal sensations in the extremities), tendonitis, purpura (small, raised purple skin lesions), testicular pain, and encephalitis (inflammation of the brain), which is a rare complication. Some individuals may be asymptomatic during infection (25-50%). Generally, laboratory evaluation during the disease course is not indicated, but, if performed, a white blood cell (WBC) count may be low or normal, and a platelet count may be low. Other diseases that can resemble the rash of rubella are scarlet fever, rubeola (measles), roseola, mononucleosis, enteroviral infections, drug rashes, and secondary syphilis. The treatment of rubella is mainly supportive care.

PREVENTION

The vaccine was developed in 1969. The vaccine that is currently used is a live virus (RA 27/3) developed from human diploid cells and confers nasopharyngeal immunity. The vaccine is routinely given to children between 12 and 15 months and revaccination occurs between 4 and 6 years old, in combination with measles and mumps (MMR). The number of rubella outbreaks has been dramatically reduced since the introduction of the vaccine. Vaccination given by single subcutaneous injection causes protective antibodies in approximately 98% of individuals and the immunity is lifelong. Reinfection among individuals who have had the immunization is 14-18% and among individuals who had natural immunity, 3-10%. Postpubertal women need to avoid pregnancy within 3 months of vaccination. Contraindications to vaccination include sensitivity to vaccine components, immunodeficiency, and persons taking antimetabolic drugs or prolonged steroids (greater than 14 days). Reactions to the vaccine include fever, lymphadenopathy (swollen glands), rash, arthritis/arthralgia (joint pains), and a more unusual reaction which may occur in young women is paresthesia in hands and knees.

CONGENITAL RUBELLA

Congenital rubella occurs when the mother has an active rubella infection and the fetus is exposed in utero. Risk of congenital malformations to the fetus is highest during the first 14 weeks of gestation. If a pregnant woman is exposed to rubella, an antibody test for rubella should be performed to determine immunity. If the mother is not immune, then therapeutic abortion is recommended or if unavailable or unacceptable, then passive immunization (immunoglobulin) may be given. Despite the use of passive immunity shortly after exposure to rubella in pregnant women, infants have been born with congenital rubella.

Infants with congenital rubella have many complications. Ophthalmologic complications include cataracts and retinopathy. Cardiac problems include patent duc-tus arteriosus and pulmonary artery stenosis. An auditory complication is sensorineural deafness. Neurologic complications are behavioral disorders, meningoen-cephalitis, and mental retardation. Other complications may include growth retardation, bone disease, hepatosplenomegaly (enlarged liver and spleen), throm-bocytopenia (low platelets), purple skin lesions (blueberry muffin rash). The care of infants with congenital rubella is primarily supportive but complex and usually occurs in neonatal intensive care units.
Rubella virus may be isolated from the throat, blood, urine, or spinal fluid of affected infants and detected by cell culture or by several different tests based on detecting viral proteins or genetic material. Infants with congenital rubella may shed virus up to 1 year after birth. Pregnant women should avoid contact with infants known to have congenital rubella.

See Also: Birth control, Immunization, Neonatal care ethics, Pregnancy

Suggested Reading

  • American Academy of Pediatrics. (2000). Rubella. In L. K. Pickering (Ed.), 2000 red book: Report of the Committee on Infectious Diseases (25th ed., pp. 495-500). Elk Grove Village, IL: Author.
  • Behrman, R. E., Kliegman, R. M., & Jenson, H. B. (Eds.) (2000). Rubella. Nelson’s textbook of pediatrics (pp. 951-953). Philadelphia: W. B. Saunders.

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