What is the rubella virus?

The rubella virus is a type of togavirus belonging to genus Rubivirus. The virus core contains single-stranded RNA (ribonucleic acid) and is surrounded by an envelope. The rubella virus can be inactivated by ultraviolet light, acidic environments, heat, lipid solvents, trypsin, formalin, and amantadine.1

How is rubella transmitted?

Moderately contagious, rubella virus transmission occurs via droplets that are shed from respiratory secretions from an infected person to a susceptible individual. The rubella virus can spread when an infected person coughs or sneezes and droplets go to a noninfected person.1,2,3

Once a person is infected, the virus replicates in the nasopharynx and regional lymph nodes and then spreads throughout the body.1

In pregnant women, transplacental infection of the fetus can occur during this time, leading to fetal damage.1,2

A person infected with rubella can be particularly contagious up to 1 week before a rash appears and up to 7 days after the appearance of a rash. However, some may not develop a rash or have any symptoms.1,3

Those who are aware of their infection need to inform coworkers, classmates, teachers, daycare staff, friends, and family, and especially women who are pregnant.3

Infants with congenital rubella syndrome (contracted during fetal exposure) can transmit rubella to those around them as they tend to shed large quantities of the virus from body secretions for up to 1 year.1

What are the pathogenesis and clinical features of rubella infection?

“Rubella” in Latin refers to “little red” as it was first considered in the early 1800s to be a variant of measles or scarlet fever. It was referred to as “third disease”. In 1814, German medical literature started to describe it as a separate disease. From then on, it was commonly known as “German measles”.1

As with most viral infections, pathogenesis and clinical features usually present in phases: incubation phase, viremia phase, and prodromal phase.

General Clinical Phases of the Rubella Infection1

Phases Characteristics

Incubation Phase

  • Days 12–23 duration from exposure

Viremia Phase (when the virus spreads within the blood)

  • Occurs within 5–7 days after exposure
  • Transplacental infection of the fetus can occur during viremia phase

Prodromal Phase (early signs and symptoms of disease)

  • Rare in young children
  • In older children and adults, typically lasts 1–5 days and may consist of:
    • Low-grade fever
    • Malaise (general feeling of discomfort)
    • Swollen lymph nodes (before rash and may last for several weeks) and rash
    • Upper respiratory symptoms

Manifestation Phase

  • Rash may occur 14–17 days after exposure:
    • First sign in young children; follows prodromal symptoms in older children and adults
    • Appears first on the face and progresses from head to foot
    • Lasts about 3 days
    • Occasionally itchy
    • Does not combine together
    • More prominent after hot bath or shower
  • Arthritis in adults
  • Other symptoms include:
    • Conjunctivitis (pink eye)
    • Testalgia (testicular pain)
    • Orchitis (inflammation of the testicles)

What are the complications of rubella?

Severe rubella complication occurs when a fetus is infected as a result of maternal exposure, also known as congenital rubella syndrome (rubella pregnancy complications).1

Long-term Concerns of Congenital Rubella Syndrome1

  • Severity dependent on time of gestation during infection
    • Most severe when infected early in gestation (≤20 weeks of gestation)
    • Rare defects when infected late in gestation (>20 weeks of gestation)
  • May affect all organs and cause a variety of congenital defects:
    • Deafness (most common, may often be the only manifestation)
    • Eye defects
    • Cardiac defects
    • Neurologic abnormalities
    • Bone lesions
    • Enlarged spleen
    • Hepatitis
    • Excessive bruising or bleeding
  • Various manifestations may have a delayed onset of 2–4 years or more:
    • Diabetes mellitus in later childhood
    • Progressive encephalopathy
    • Autism
  • Reinfection may occur

Other complications in the general population as a result of rubella infection can vary depending on age and gender.1

Other Complications, Dependent on Age and Gender

Complications Incidence Rates Details

Joint pain or arthritis

Up to 70% (adult females)
  • Usually occurs at the same time as the rash and lasts for up to a month
  • Affects fingers, wrists, and knees
Rare (children)

(inflammation of the brain)

0.016% (adult females)
  • Mortality as a result of encephalitis can vary from 0%–50%
Rare (children)

Hemorrhagic manifestation

0.033% (more often in children)
  • May present as:
    • Thrombocytopenic purpura (excessive bruising and bleeding)
    • Low platelets
    • Vascular damage
  • May occur in the:
    • Gastrointestinal tract
    • Brain
    • Kidneys

How is rubella diagnosed?

Since rubella infection can appear similar to other rash illnesses or may be asymptomatic, a positive viral culture is needed to make a positive rubella diagnosis. Virus can be isolated from nasal, blood, throat, urine, and cerebrospinal fluid samples of rubella and congenital rubella syndrome patients. Laboratory confirmation of the rubella virus is helpful for epidemiologic purposes.1

How does geography affect the disease pattern of rubella?

In Temperate Climates, Incidence of Rubella Is Highest In the Late Winter and Early Spring

The incidence of rubella is highest in the late winter and early spring.1


The incidence of rubella is usually highest in the dry cool season.4

Downloadable Resource

The resource below has been created to help your patients, their parents, or their legal representatives, learn about rubella while they wait in the doctor’s office.

What you should know about rubella
PDF about rubella that you can download and share with patients, their parents, or their legal representatives.

CDC Disease Information

DISCLAIMER: By clicking on the link below, you will be directed away from to another website. Merck does not review or control the content of the site to which the hyperlink connects; therefore, the hyperlink does not constitute an endorsement by Merck.

CDC, Centers for Disease Control and Prevention



  1. Centers for Disease Control and Prevention (CDC). Rubella. In: Hamborsky J, Kroger A, Wolfe S, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases. 13th ed. Washington, DC: Public Health Foundation; 2015:325–340. Accessed January 22, 2020.


  1. Gershon AA. Rubella virus (German measles). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas and Bennett’s Principles and Practice of Infectious Diseases. Vol 2. 9th ed. Philadelphia, PA: Elsevier Saunders; 2020:2007-2012.


  1. Centers for Disease Control and Prevention (CDC). Transmission. Updated September 15, 2017. Accessed January 22, 2020.


  1. World Health Organization (WHO). Measles and rubella in the South-East Asia. Accessed February 5, 2020.

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