A prolonged mumps outbreak among highly vaccinated Aboriginal people in the Kimberley region of Western Australia
Revle D Bangor-Jones, Gary K Dowse, Carolien M Giele, Paul G van
Buynder, Meredith M Hodge and Mary M Whitty
MJA 2009; 191 (7): 398-401
To describe a prolonged outbreak of mumps in the Kimberley region of
Western Australia in 2007–2008.
Descriptive analysis of all mumps cases notified to the WA Notifiable
Infectious Diseases Database for the period 1 July 2007 to 30 June 2008.
Main outcome measures:
Notified cases of mumps by patients’ place of residence, age,
Indigenous or non-Indigenous ethnicity, vaccination status and method
84% (153/183) of mumps notifications in WA over the study period
occurred in the Kimberley region or were directly linked to Kimberley
cases. Median age of patients was 18 years (range, 2–63 years), and
54% of patients were aged less than 20 years. Almost all (92%) were
Australian Aboriginal people; 67% (102/153) had received at least one
dose of mumps vaccine, and 52% had received two doses. The highest
notification rate (1816 cases per 100 000 population) was in the
Aboriginal 15–19-years age group, and 92% of these patients had
received at least one dose of mumps vaccine. Almost all outbreak cases
(94%) were laboratory confirmed. Genotyping was performed on 20 mumps
virus isolates: all were genotype J.
A prolonged outbreak of mumps occurred in a well defined, highly
vaccinated, predominantly young Aboriginal population in the remote
Kimberley region of WA. This outbreak raises questions about the
effectiveness and scheduling of the current vaccine (which is genotype
A-derived), especially for Aboriginal people. Surveillance of
circulating mumps virus genotypes and neutralisation studies will help
in evaluating the protection provided by the current vaccine against
genotypically different strains.