German Measles (Third Disease, Rubella)

Basics

Description

  • Rubella derived from Latin, meaning “little red.”
  • Disease initially considered variant of measles
  • Viral infection characterized by mild symptoms (often subclinical), with an erythematous rash progressing from head to toes
  • Congenital rubella syndrome can be devastating.

Epidemiology

  • Spread person to person via airborne transmission; worldwide infection
  • Infection most contagious when rash is erupting. However, virus may be shed beginning 7 days before rash to 14 days after.
  • Infants with congenital rubella syndrome may shed virus for up to 1 year.
  • In temperate regions, peaks in late winter and early spring
  • Infection occurs equally in following age groups: <5 years, 5 to 19 years, and 20 to 39 years.
    • In prevaccine era, annual incidence of infection in the United States was ∼58 per 100,000 population.
    • 2004: no longer endemic in the United States
    • 2004 to 2012: 79 reported cases, mostly in unvaccinated individuals born overseas
  • Congenital rubella syndrome
    • 1964: 20,000 newborns
    • 1980s: reported rarely, with <5 cases annually
    • 1990 to 1991: ∼30 cases reported annually
    • 2004 to 2012: total of 6 cases reported to Centers for Disease Control and Prevention (CDC), only 1 with mother born in the United States

General Prevention

  • Prevention of congenital rubella syndrome is main objective of vaccination programs.
  • Rubella vaccine
    • Current strain of vaccine (RA 27/3, developed at the Wistar Institute in Philadelphia) was licensed in 1979 and has replaced all other strains.
    • Given as part of MMR vaccine at 12 to 15 months and again at 4 to 6 years
    • Immunity occurs in 95% of those vaccinated and is thought to be lifelong.
    • Important to ensure full vaccination for preschool-aged children
    • Vaccine virus is not communicable: Pregnant women and persons who are immunodeficient (except asymptomatic HIV infection) should not receive vaccine, but household contacts should.
  • Isolation
    • Pregnant women should avoid contact with source patient.
    • Postnatal: Droplet precautions and/or school exclusion is indicated for 7 days after onset of rash.
    • Congenital: contact isolation until first birthday or until two nasopharyngeal and urine cultures consecutively negative

Pathophysiology

  • Respiratory transmission
  • Replication in nasopharynx and regional lymph nodes
  • Viremia 5 to 7 days after exposure, with spread of virus throughout body
  • In congenital rubella syndrome, transplacental infection of fetus occurs during viremia.

Etiology

Rubella virus

  • Classified as a Rubivirus in the Togaviridae family
  • RNA virus with single antigenic type
  • First isolated in 1962 by Parkman and Weller

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