title: The changing epidemiology of invasive pneumococcal disease in aboriginal and non-aboriginal western Australians from 1997 through 2007 and emergence of nonvaccine serotypes.
abstract: BACKGROUND. In 2001, Australia introduced a unique 7-valent pneumococcal conjugate vaccine (7vPCV) 2-, 4-, and 6-month schedule with a 23-valent pneumococcal polysaccharide vaccine (23vPPV) booster for Aboriginal children, and in 2005, 7vPCV alone in a 2-, 4-, and 6-month schedule for non-Aboriginal children. Aboriginal adults are offered 23vPPV but coverage is poor. We investigated trends in invasive pneumococcal disease (IPD) in Western Australia (WA). METHODS. Enhanced IPD surveillance has been ongoing since 1996. We calculated IPD incidence rates for Aboriginal and non-Aboriginal Australians before and after introduction of 7vPCV. RESULTS. A total of 1792 cases occurred during the period 1997-2007; the IPD incidence rate was 47 cases per 100,000 population per year among Aboriginal people and 7 cases per 100,000 population per year in non-Aboriginal people. After introduction of 7vPCV, IPD rates among Aboriginal children decreased by 46% for those <2 years of age and by 40% for those 2-4 years of age; rates decreased by 64% and 51% in equivalent age groups for non-Aboriginal children. IPD rates decreased by >30% in non-Aboriginal people 50 years of age but increased among Aboriginal adults (eg, from 59.1 to 109.6 cases per 100,000 population per year among those 30-49 years of age). Although IPD due to 7vPCV serotypes decreased in all age groups, IPD incidence due to non-7vPCV serotypes increased, and it almost doubled among Aboriginal adults 30-49 years of age (from 48.3 to 97.0 cases per 100,000 population per year). Among non-Aboriginal children, 37% of IPD is now due to serotype 19A. CONCLUSIONS. IPD incidence rates have decreased markedly among children and non-Aboriginal adults with a 3-dose infant 7vPCV schedule. However, IPD due to non-7vPCV serotypes has increased and is of particular concern among young Aboriginal adults, for whom an intensive 23vPPV campaign is needed. An immunization register covering all age groups should be established.
authors.affiliation: Telethon Institute for Child Health Research, Centre for Child Health Research, Queensland, Australia. deborahl@ichr.uwa.edu.au
authors.forename: Deborah
authors.initials: D
authors.lastname: Lehmann
authors.forename: Judith
authors.initials: J
authors.lastname: Willis
authors.forename: Hannah C
authors.initials: HC
authors.lastname: Moore
authors.forename: Carolien
authors.initials: C
authors.lastname: Giele
authors.forename: Denise
authors.initials: D
authors.lastname: Murphy
authors.forename: Anthony D
authors.initials: AD
authors.lastname: Keil
authors.forename: Catherine
authors.initials: C
authors.lastname: Harrison
authors.forename: Kathy
authors.initials: K
authors.lastname: Bayley
authors.forename: Michael
authors.initials: M
authors.lastname: Watson
authors.forename: Peter
authors.initials: P
authors.lastname: Richmond
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D005006:Ethnicity; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology* / Q000517:prevention & control; D022242:Pneumococcal Vaccines / Q000276:immunology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification*; D014904:Western Australia / Q000453:epidemiology; D055815:Young Adult
chemical_list: D022242:Pneumococcal Vaccines