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 direct or droplet transmission from nasopharyngeal secretions
• 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
• Incubation period 12 to 23 days, with mean 17 days
• 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 2017: 107 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 2017: total of 17 cases reported to Centers for Disease Control and Prevention (CDC)

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

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 measles, mumps, and rubella (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.