Congenital Rubella Syndrome: Vaccine Preventable Diseases Surveillance Standards
Overview
Rubella is an acute viral disease often affecting
susceptible children and young adults worldwide.
Although it causes only a mild clinical illness in these
groups, its public health importance is due to the
teratogenic potential of the virus resulting in congenital
rubella syndrome (CRS). From just before conception
through the first 8–10 weeks of gestation, rubella
infection of the pregnant woman can result in multiple
fetal abnormalities in up to 90% of cases, and may result
in miscarriage or stillbirth. CRS defects can affect any
organ system, including ophthalmic, auditory, cardiac,
neurologic, hepatic and haemotologic.
After 18 weeks
of gestation, the risk of CRS is low. The most common
defects of CRS are hearing impairment and deafness, eye
defects (cataracts, congenital glaucoma or pigmentary
retinopathy) and cardiac defects. Infected infants can
shed high amounts of rubella virus from body secretions
for up to one year, thus potentially causing outbreaks.
Infants that survive the neonatal period may face serious
developmental disabilities (such as deafness) and have an
increased risk for developmental delay (such as autism)
and autoimmune diseases (diabetes type 1, thyroiditis).
In some cases of rubella infection during pregnancy,
particularly after 20 weeks of gestation, the fetus can
be infected but not develop the signs and symptoms of
CRS. These infants are classified as congenital rubella
infection (CRI), and also shed rubella virus.
Before introduction of rubella vaccination, epidemics
of rubella have resulted in rates of CRS of 0.8–4.0 per
1,000 live births.
Rubella vaccine has been highly
effective at reducing the burden of CRS, and vaccination
has led to elimination of rubella and CRS from several
European and Western Pacific countries and the Pan
American Health Organization Region. However,
insufficient population vaccination coverage can result
in a median age shift of rubella cases to young adults,
which may result in more CRS cases.