Rubella

Microbiology

Rubella, also known as German measles, is a viral infection caused by the togavirus. Following the introduction of the MMR vaccine it is now rare with most years yielding no conformed cases in the UK. If contracted during pregnancy there is a risk of congenital rubella syndrome.

Epidemiology

outbreaks more common around winter and spring
incubation period is 14-21 days
individuals are infectious from 7 days before symptoms appear to 4 days after the onset of the rash

Spread

Primarily spread via droplet spread from respiratory secretions
Less commonly spread by direct contact with an infected person
Transplacental spread to fetus

Clinical features

prodrome e.g. low grade fever
rash: maculopapular, initially on face before spreading to whole body, usually fades by 3rd-5th day
lymphadenopathy: suboccipital and postauricular

The maculopapular rash in a patient with rubella. Click on image to enlarge

Complications

arthritis
thrombocytopenia
encephalitis
myocarditis
congenital rubella syndrome if contracted in pregnancy (see below)

Rubella in pregnancy
If contracted during pregnancy there is a risk of congenital rubella syndrome.

Risk:

In first 8-10 weeks risk of damage to fetus is as high as 90%
Fetal damage is rare after 16 weeks

Features of congenital rubella syndrome:

sensorineural deafness
congenital cataracts
congenital heart disease (e.g. patent ductus arteriosus)
growth retardation
hepatosplenomegaly
purpuric skin lesions
'salt and pepper' chorioretinitis
microphthalmia
cerebral palsy

Diagnosis:

IgM antibodies are raised in women recently exposed to the virus

Investigation

Serological or PCR testing is gold standard investigation
Local Health Protection Unit (HPU) will provide testing kit

Management

No specific treatment
Antipyretics for fever
Advise on exclusion from school for 5 days from onset of rash
Infection in pregnancy should prompt referral to obstetrics
Notifiable disease requires notification of local authority or UKHSA health protection team

Key Points

Incubation period is 2 to 3 weeks (remember incubation period for measles, mumps and rubella are all around 2 weeks!)
Congenital infection is associated significant cardiovascular and neurological defects as well as increased risk of fetal death.
Rubella (German measles) rash usually starts behind the ears. Measles also usually starts on the head.
Rubella & Measles are both infective until around 4 days after the rash appears.
MMR vaccination schedule: MMR is given twice, at 12 months and preschool (usually age 4).