Yet another case of vaccine failure - this one amongst Australian Aboriginal communities in WA

[Guest guest]

A prolonged mumps outbreak among highly vaccinated Aboriginal people

in the Kimberley region of Western Australia

Revle D Bangor-, K Dowse, Carolien M Giele, G van

Buynder, Meredith M Hodge and 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.

Design:

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

of diagnosis.

Results:

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.

Conclusion:

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.