Chapter last reviewed and updated in May 2012.
New Zealand Epidemiology
There have been no reported cases of congenital rubella in New Zealand since 1998. Internationally, the number of rubella and congenital rubella cases remains high in developing countries, including many Pacific Islands, where routine childhood vaccination is not available or has only recently become available.
More detailed epidemiological information is available on the Institute of Environmental Science and Research (ESR) surveillance website.
In general, the younger the fetus when infected, the more severe the illness. Severe cases may spontaneously abort, or have multiple manifestations in infancy; mild cases may have only a single manifestation. The most common anomalies are deafness, cataract or glaucoma, congenital heart disease and mental retardation. In addition, infants with congenital rubella syndrome are often growth retarded and may have radiolucent bone disease, hepatosplenomegaly, thrombocytopenia and purpuric skin lesions.
Laboratory criteria for diagnosis
Laboratory confirmation requires at least one of the following:
- demonstration of rubella-specific IgM antibody
- infant rubella antibody level that persists at a higher level and for a longer period than expected from passive transfer of maternal antibody (that is, rubella titre that does not drop at the expected rate of a twofold dilution per month)
- isolation of rubella virus by culture
- detection of rubella virus nucleic acid.
- Under investigation: A case that has been notified, but information is not yet available to classify it as probable or confirmed.
- Probable: A clinically compatible illness.
- Confirmed: A clinically compatible illness that is laboratory confirmed.
- Not a case: A case that has been investigated and subsequently found not to meet the case definition.
Spread of infection
14–23 days, commonly 16–18 days.
Mode of transmission
Infants with congenital rubella shed rubella virus in their pharyngeal secretions and urine.
Period of communicability
Infants with congenital rubella may shed the virus for months after birth and should be considered infectious until they are 1 year of age.
Attending medical practitioners or laboratories must immediately notify the local medical officer of health of suspected cases. Notification should not await confirmation.
Management of case
Ascertain relevant history of maternal vaccination, any maternal symptoms, possible contacts and travel.
Ensure laboratory confirmation by serology or detection of virus in clinical specimens has been attempted. Nasal, throat, urine, blood and cerebrospinal fluid specimens can yield the virus, especially in congenitally infected infants.
In health care facilities, infants with congenital rubella syndrome should be managed under contact and droplet isolation precautions until urine and pharyngeal cultures are negative or until approximately 1 year of age. Non-immune pregnant women, in particular, and also non-immune women of childbearing age should not have contact with an infectious case.
Advise caregivers of the nature of the infection and its mode of transmission.
Management of contacts
All people with close unprotected contact (for example, household, workplace, school, military camp) with the case during the week before onset of illness or during the subsequent period of communicability.
Other control measures
Identification of source
Refer to ‘Other control measures’ in the separate chapter on rubella.
Ensure complete case information is entered into EpiSurv.
If a cluster of cases occurs, inform the Ministry of Health Communicable Diseases Team and outbreak liaison staff at ESR, and complete the Outbreak Report Form.