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. Immunization with a live, attenuated vaccine, in association with the measles and mumps vaccine, is highly recommended. The first dose is administered between 12–15 months of age and the second dose between 4–6 years of age. Complications of infection during pregnancy may cause congenital rubella syndrome with severe malformations (e.g., hearing loss, cataracts, heart defects, intellectual disabilities).

• A rare disease in the US following the implementation of the MMR vaccine

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, 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
    • ^[4]
• 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 anti-inflammatory drugs
• For treatment of congenital rubella syndrome and seronegative women following exposure to rubella virus, see congenital rubella syndrome

• 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.

Immunization ^[3][5][6]

• Live attenuated virus that is administered in combination with the measles and mumps vaccine (see immunization schedule)
• Two vaccinations are recommended because of potential non-responders (5%):
  • First dose: 12–15 months of age
  • Second dose: 4–6 years of age or at least 28 days following the first dose.
• Check vaccination status
  • ELISA (preferred method), latex agglutination, hemagglutination inhibition, or immunofluorescent antibody assay.
  • A titer of ≥ 1:32 indicates immunity to rubella.

Women of child-bearing age, without vaccination or unclear vaccine status, should be vaccinated prior to pregnancy!

Precautions during infection

• Patients with rubella infection should be isolated for 7 days after the onset of the rash.
• Precautions regarding droplet transmission should be taken.

Reporting regulations

• Rubella cases need to be reported to the CDC or to the National Center for Immunization and Respiratory Diseases (NCIRD) within 24 hours of confirmation.