Synonym: German measles

Pathophysiology

• An RNA virus (genus Rubivirus, family Togaviridae) with man as the only known host:
  • There is only one major antigenic type.
  • It is transmitted as airborne droplets between close contacts (unlike most togaviruses which are arthropod-borne).
  • The incubation period is 14–21 days with patients being infectious for up to 7 days before and 5 days after symptoms appear.
  • Infectivity is greatest just before and on the day of symptoms appearing.
• Its major complication is the congenital rubella syndrome:
  • This causes a wide variety of malformations affecting the cardiac, ocular, central nervous and skeletal systems when a pregnant mother is infected.
  • This is still a problem in many developing countries.⁴
  • It could become more of a problem again in developed countries in certain vulnerable groups (such as unvaccinated immigrants with no immunity).^5,6

Epidemiology⁷

• Rubella was endemic in the UK before the vaccination programme was established. It affected mainly young children between the ages of 4 and 9 years and occurred in epidemics every 6 to 9 years. However, because it is only moderately infectious, as many as 20% of women were left vulnerable to infection during pregnancy. Significantly, before the vaccination programme:
  • There were conservatively 70 cases of congenital rubella syndrome (CRS) per year and hundreds during epidemic years. Such statistics do not adequately highlight all the associated morbidity of CRS.
  • The ratio of therapeutic abortions to cases of CRS was approximately 10:1. This means that, for every 70 cases of CRS, around 700 pregnancies would have been terminated each year.
• Selective rubella vaccination was introduced in the UK in 1970 for prepubertal girls and nonimmune women of child-bearing age, to protect them from the risks of CRS.
• Universal rubella vaccination was introduced in 1988 with the MMR vaccine as part of the childhood immunisation programme. The combined measles and rubella (MR) vaccine was given in a 1994 catch-up campaign. In 1996 the two-dose MMR regimen was implemented.
• Following this vaccination programme, rubella is uncommon in the UK and CRS is very rare.
  • In 2008 there were only 888 notifications of rubella (with only 16 of these cases laboratory-confirmed).
  • Initially the vaccinations did not interrupt the circulation of rubella. Nonimmunised women remained vulnerable to infection. Between 1971 and 1975 there were an average of 48 cases of CRS every year, with 742 therapeutic terminations carried out for women contracting rubella during pregnancy.
  • Between 1996 and 2000 a total of 16 congenital rubella births were registered with the National Congenital Rubella Surveillance Programme.⁷ Since 2000, there have been only about 10 reports of CRS in the UK - most of these cases in women born overseas and not adequately immunised.
• Recently, uptake of the MMR vaccine has decreased to 80% (or less in some areas) because of unfounded fears about the MMR vaccine. There is now concern that this will lead to outbreaks of rubella and CRS.
• It should be remembered that rubella remains endemic in many developing countries, and that over 100,000 children worldwide every year are born with CRS.

Presentation

• Symptoms:
  • Prodromal phase of lassitude, fever, headache, conjunctivitis and anorexia with rhinorrhoea very similar to a cold. The prodrome may be absent in children and tends to be more noticeable in adults.
  • The rash then develops (it may be absent, especially in young children) – initially, pink discrete macules that coalesce, starting behind the ears and on the face, spreading to the trunk and then the extremities.
  • Cervical, suboccipital, and postauricular lymphadenopathy is characteristic and may precede the rash.
  • Constitutional symptoms are usually mild (can be more prominent in adults).
  • In older patients arthralgia is common.
• Signs:
  • There may be petechiae on the soft palate (Forschheimer sign), but this is not diagnostic for rubella.
  • The rash is shown in close up, but it should be remembered that clinical diagnosis is unreliable.

Differential diagnosis

• Contact dermatitis
• Erythema multiforme/drug eruptions
• Measles
• Cutaneous manifestations of syphilis
• Scarlet fever
• Kawasaki disease
• Arthropod-borne infections (for example, Rocky Mountain spotted fever)

Investigations

Clinical diagnosis is unreliable since symptoms are often fleeting and mimicked by other viruses. In particular, the rash is not diagnostic.

• Investigations are not usually necessary (although it is important to confirm infection in pregnant women - see below).
• Confirmation of diagnosis can be made early by polymerase chain reaction (PCR) test of samples from the oropharynx, urine and conjunctiva in infants.⁸
• Presence of rubella IgM is diagnostic (it may persist for up to a year) and persistence of IgG after 6 months is strongly suggestive.
• FBC may show a low WBC count with an increased proportion of lymphocytes and thrombocytopenia (usually resolves in a month).
• Rubella virus may be identified via throat swab, blood or urine examination, and CSF.

Management

• There is no specific treatment.
• Keep the child away from school for 7 days after the rash appears.
• Use antipyretics for fever – avoid aspirin in children due to the danger of Reye's syndrome.
• Ask about any contact with pregnant women.
• Where suspected infection occurs in a pregnant woman, it should be confirmed by investigation, in liaison with a virologist, and counselling should be given about the dangers to the fetus. Management requires referral and expert support.

Complications

• Complications occur rarely
• Rubella encephalopathy may occur about 6 days after the rash (usually there is full recovery in a few days without sequelae)
• Orchitis
• Guillain Barré syndrome/neuritis
• Panencephalitis

Prevention

• The advice is that children should be excluded from school for 5-7 days after onset of the rash.⁹ This is not an effective preventative measure, as the infection is most contagious before appearance of the rash.
• Vaccination via MMR in the second year of life plus a preschool booster, with antenatal screening for rubella susceptibility.
• Where nonimmunity to rubella is discovered during pregnancy, immunisation after delivery offers protection for future pregnancies.

Rubella in pregnancy

See separate article Congenital Rubella Syndrome.

Historical

• Initially considered a variant of measles ('first disease') or scarlet fever ('second disease'), and called 'third disease' ('fourth disease' was Duke's disease - may have been a staphylococcal or enteroviral infection, 'fifth disease' being parvovirus infection or erythema infectiosum, and 'sixth disease' being roseola infantum from herpes virus 6).
• Described first in the German medical literature as 'Rötheln', in the mid-18th century, and as a separate entity in 1814 by George Maton - hence 'German measles'.
• Given the name rubella in 1866 by Royal Artillery surgeon Henry Veale.
• The American physician Alfred Hess (1875-1933) postulated a viral aetiology in 1914. He also wrote books on scurvy and rickets, showing that the missing factor for scurvy was abundant in citrus fruits and tomatoes, and introduced sunlight treatment for rickets.
• The enveloped RNA rubella virus itself was isolated in 1962 by Parkman and Weller. It is a togavirus, genus Rubivirus, and is most closely related to group A arboviruses (for example, Eastern and Western equine encephalitis viruses).

Document references

1. Rubella (German Measles), Health Protection Agency; general information
2. Elliman DA, Bedford HE; Measles, mumps and rubella vaccine, autism and inflammatory bowel disease: advising concerned parents. Paediatr Drugs. 2002;4(10):631-5. [abstract]
3. Friederichs V, Cameron JC, Robertson C; Impact of adverse publicity on MMR vaccine uptake: a population based analysis of vaccine uptake records for one million children, born 1987-2004. Arch Dis Child. 2006 Jun;91(6):465-8. Epub 2006 Apr 25. [abstract]
4. Banatvala JE, Brown DW; Rubella.; Lancet. 2004 Apr 3;363(9415):1127-37. [abstract]
5. Tookey P; Rubella in England, Scotland and Wales. Euro Surveill. 2004 Apr;9(4):21-3. [abstract]
6. Sheridan E, Aitken C, Jeffries D, et al; Congenital rubella syndrome: a risk in immigrant populations. Lancet. 2002 Feb 23;359(9307):674-5. [abstract]
7. Notifications of Infectious Diseases (NOIDs), Health Protection Agency (HPA)
8. Cooray S, Warrener L, Jin L; Improved RT-PCR for diagnosis and epidemiological surveillance of rubella. J Clin Virol. 2006 Jan;35(1):73-80. Epub 2005 Jul 12. [abstract]
9. Guidelines on Rubella (German Measles), Health Protection Agency (2009)

Internet and further reading

• Rubella, Clinical Knowledge Summaries (December 2009)

Acknowledgements