RUBELLA

Rubella, also known as German measles or three-day measles, is a mild, self-limited viral disease. Humans are the only known natural host. In up to 50 percent of persons who are not immune, a diffuse maculopapular red rash develops in two to three weeks after contact with secretions from the mouth or nose of an infected person. From 20 to 50 percent of those infected do not develop symptoms, however. Along with the rash, infected persons may experience enlarged lymph glands, conjunctivitis, and runny nose. Adult women may also experience joint pain or swelling.

When infection occurs early in pregnancy, the risk of the fetus being infected may be as high as 90 percent. Consequences of fetal infection include miscarriages, stillbirths, and severe birth defects, known as congenital rubella syndrome (CRS). Known defects include cataracts, heart defects, and hearing impairment. Up to 20 percent of the infants born to mothers infected during the first half of their pregnancy have CRS.

Because many people with rubella do not have symptoms, and because many rash illnesses look similar to rubella, a laboratory test is required to confirm rubella infection. A blood test can be used to detect rubella antibodies, and the virus can be cultured and isolated from a sample of blood, nasal or throat secretion, urine, spinal fluid, or body tissues such as cataracts.

Rubella circulates year-round, with a regular seasonal peak during springtime. Before the rubella vaccine was used in the United States, major epidemics occurred every six to nine years. The last major U.S. rubella epidemic occurred in 1964–1965 and caused an estimated 12.5 million cases of rubella and 20,000 cases of CRS in live-born infants. Prior to vaccine use, rubella occurred mainly among children. With the success of the U.S. rubella immunization program, the incidence of rubella has decreased by 99 percent to a reported 267 cases of rubella and six cases of CRS in 1999. In the United States, most cases of rubella now occur mainly among adults who were born in countries that do not have a long history of widespread vaccination.

In 1969, three rubella vaccines were licensed for use in the United States. In 1979, the currently used vaccine—called RA27/3—was introduced, replacing the other three. More than 95 percent of those vaccinated develop lifelong immunity. In the United States, one dose of rubella vaccine is recommended for all susceptible persons twelve months of age and older, unless vaccination is contraindicated.

Side effects following vaccination include low-grade fever, rash, joint pain and swelling, and lymphadenopathy. Joint pain and transient joint swelling tend to be more severe in vaccinated women than in men or children. Overall, joint pain and swelling tend to be more severe and last longer in persons who have the natural rubella disease than those who receive the rubella vaccine.

Although use of rubella vaccine is contraindicated in pregnant women or women planning pregnancy within three months, the U.S. registry on inadvertent vaccination in pregnancy has documented that all infants listed in the registry were free of defects associated with CRS. These data are consistent with results reported from other countries. Other groups that should not be given the vaccine include persons with immunodeficiency diseases or compromised immune systems and those who have recently received immunoglobulin or have severe fever.

BIBLIOGRAPHY

Cooper, L. Z., and Alford, C. A., Jr. (2001). "Rubella." In Infectious Diseases of the Fetus and Newborn Infant, 5th edition, eds. J. S. Remington and J. O. Klein. Philadelphia, PA: W. B. Saunders.

"Measles, Mumps, and Rubella—Vaccine Use and Strategies for Elimination of Measles, Rubella, and Congenital Rubella Syndrome and Control of Mumps: Recommendations of the Advisory Committee on Immunization Practices (ACIP)." Mortality and Morbidity Weekly Report 47(RR-8):1–57.

Plotkin, S. A. (1999). "Rubella Vaccine." In Vaccines, 3rd edition, eds. S. A. Plotkin and W. A. Orenstein. Philadelphia, PA: W. B. Saunders Company.