Rubella

Rubella, or German measles, is an infectious disease that is caused by the rubella virus. Since the introduction of the measles, mumps, and rubella (MMR) vaccine, it is a relatively rare condition. Rubella is transmitted via airborne droplets and has a mild clinical course. The clinical presentation begins with nonspecific flu-like symptoms and post-auricular and/or suboccipital lymphadenopathy. An exanthem phase may overlap or follow; this phase is characterized by a rash that typically starts behind the ears and progresses distally, developing into a generalized maculopapular rash. Rubella is usually self-limiting and involves symptomatic treatment. Complications of infection during pregnancy may cause congenital rubella syndrome with severe malformations (e.g., hearing loss, cataracts, heart defects, intellectual disabilities). The rubella vaccine is a combination vaccine that protects against measles, mumps, and rubella (MMR vaccine); the MMRV vaccine also protects against varicella. Immunization is recommended for all children, in addition to adults without evidence of immunity to measles, mumps, and/or rubella.

• A rare disease in the US following the implementation of the MMR vaccine
• Risk factors: See “Risk factors for measles, mumps, and/or rubella.”

Epidemiological data refers to the US, unless otherwise specified.

• Pathogen
  • Rubella virus, an RNA virus of the family Matonaviridae
  • Prior to 2019, the rubella virus was classified as the sole member of the Rubivirus genus in the Togaviridae family. ^[1]
  • Humans are the only hosts.
• Route of transmission
  • Respiratory droplets or transplacental
  • Infectivity: 7 days prior to and 7 days following the appearance of an exanthem
  • Low infectivity and virulence

Patients with rubella infection are asymptomatic in ∼ 50% of cases. Young children have a far milder course than older children and adults; the latter group often presents with prodromal symptoms, other systemic complaints (e.g., arthritis), and a longer duration of infection.

Prodromal phase

• Incubation period: 2–3 weeks after infection
• Duration: 1–5 days
• Findings
  • Post-auricular and suboccipital lymphadenopathy and occasionally splenomegaly
  • Mild and nonspecific symptoms such as low-grade fever; , mild sore throat, cough, conjunctivitis, headache, and aching joints
  • Forchheimer sign: enanthem of the soft palate

Exanthem phase

• Duration: lasts 2–3 days
• Findings
  • Fine, nonconfluent, pink maculopapular rash
    • Begins at the head, primarily behind the ears, extends to the trunk and extremities, sparing palms and soles
    • Rash may be itchy in adults
  • Polyarthritis

Although rubella infection may be considered a clinical diagnosis; , laboratory confirmation is necessary for certain patient groups to assess the risk of complications such as e.g., congenital rubella in pregnant women or encephalitis.

• Laboratory tests ^[2][3]
  • CBC: leukocytopenia with relative lymphocytosis and increased plasma cells
  • Confirmatory test: serology
    • Detection of IgM antibodies
    • ≥ 4-fold increase in IgG titer
• For prenatal and congenital diagnosis → see congenital rubella syndrome.

• Differential diagnoses of pediatric rashes

The differential diagnoses listed here are not exhaustive.

• Symptomatic treatment
  • Severe pruritis: antihistamines
  • Severe polyarthritis: rest and nonsteroidal antiinflammatory drugs
• For treatment of congenital rubella syndrome and seronegative women following exposure to rubella virus, see “Congenital rubella syndrome.”
• Isolate patients with confirmed infection. ^[4]
  • All individuals: Isolate for 7 days from the onset of rash.
  • Hospitalized patients: Initiate droplet precautions.

Rubella is a nationally notifiable disease; report all cases to the appropriate health departments. ^[5]

• Chronic arthritis (especially women)
• Thrombocytopenic purpura
• Rubella during pregnancy (TORCH infection): congenital rubella syndrome
• Rare: rubella encephalitis, bronchitis, otitis, myocarditis, pericarditis

We list the most important complications. The selection is not exhaustive.

• The disease usually has a benign course and the exanthem disappears rapidly.
• Joint pain may persist for several weeks; arthralgia may persist up to a month in adults.

Vaccination ^[6][7][8]

Administer a live attenuated rubella vaccine; (i.e., MMR vaccine, MMRV vaccine) according to the ACIP immunization schedule. See the following:

• Immunizations for measles, mumps, and rubella
• ACIP immunization schedule
• Contraindications to live vaccines (e.g., pregnancy, immunocompromise)

Evidence of immunity to rubella ^[9][10]

• See “Indications to test for immunity to rubella” and “Evidence of immunity to measles, mumps, and/or rubella.”
• If laboratory evidence of immunity to rubella is required, perform serologic testing. ^[9][10]
  • IgG measurement by enzyme immunoassay is preferred.
  • A rubella IgG titer > 10 IU/mL indicates immunity to rubella. ^[9]

Exposure control ^[4][11]

For confirmed cases of rubella:

• Patients: Isolate for 7 days from the onset of rash to prevent further transmission .
• Exposed contacts without evidence of immunity to measles, mumps, and/or rubella: Quarantine for 23 days from the onset of rash in the last known exposure. ^[4][11]

Women of reproductive age without evidence of immunity to rubella should be vaccinated prior to pregnancy to prevent congenital rubella syndrome. ^[12]