Invasive pneumococcal disease in Australia, 2006

Area of Science:

• Public Health
• Epidemiology
• Infectious Diseases

Background:

• Enhanced surveillance for invasive pneumococcal disease (IPD) in Australia has provided comparative data since 2002.
• In 2006, 1,445 cases of IPD were reported, with notification rates varying by state, territory, and geography.

Purpose of the Study:

• To analyze IPD trends in Australia in 2006.
• To assess the impact of the 7-valent pneumococcal conjugate vaccine (7vPCV) program on IPD rates.
• To highlight disparities in IPD incidence, particularly among Indigenous Australians.

Main Methods:

• National surveillance data from all Australian states and territories for 2006.
• Comparative analysis of data from 2002 to 2006.
• Serotype identification for notified IPD cases.

Main Results:

• Overall IPD notification rate was 7 per 100,000 population, with highest rates in the Northern Territory.
• IPD was most common in the elderly (≥85 years) and one-year-old children.
• The rate of IPD in Indigenous Australians was 4.3 times higher than in non-Indigenous Australians.
• Rates of IPD caused by 7vPCV serotypes decreased by 78% in children under two years post-vaccination program introduction.
• Serotypes covered by 7vPCV accounted for 43% of IPD cases, while 85% were covered by the 23-valent polysaccharide pneumococcal vaccine (23vPPV).

Conclusions:

• The 7vPCV immunization program has significantly reduced IPD caused by vaccine serotypes, especially in young children.
• Persistent disparities in IPD rates exist between Indigenous and non-Indigenous Australians.
• Antimicrobial resistance to penicillin and cephalosporins remains low in invasive pneumococcal isolates.