Humans are the only source of rubella infection. Asymptomatic infection is common. In the pre-vaccine era the highest incidence of clinical cases occurred in the spring among 5- to 9-year-old children, and 80–90 percent of adults were immune to rubella. Extensive outbreaks of rubella occurred every six to nine years, in which many children were affected by CRS. Immunisation against rubella, introduced to prevent the occurrence of CRS, has resulted in a signiﬁcant reduction, especially where there is extensive use of the rubella vaccine.
Rubella immunisation was introduced in 1970 (see Appendix 1) and rubella has been a notiﬁable disease since 1996. The last rubella outbreak in 1995–1996 mostly involved young adult males, who would not have been offered immunisation. This emphasises the need to immunise both boys and girls to reduce the risk of exposure in pregnant women, as well as to reduce illness in men.
In 2013 there was one notified case of rubella and no laboratory-confirmed cases. Four cases of rubella were notified in 2012, of which three were laboratory confirmed.2 Since the last rubella outbreak there has been a steady decrease in the number of cases notified each year, except for an increase in notifications in 2011 (22 cases) during the measles outbreak (Figure 18.1). All cases in 2012 were in males: two from the 1–4 years age group, and one each from the 20–29 years and 40–49 years age groups. Of the two cases for which risk factor information was recorded, one reported overseas travel during the incubation period for this disease. One hospitalisation and no deaths due to rubella were reported.
There have been no reported cases of CRS in New Zealand since 1998.
Source: Ministry of Health and the Institute of Environmental Science and Research