Invasive pneumococcal disease in Australia, 2009 and 2010

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• Enhanced surveillance for invasive pneumococcal disease (IPD) was conducted across Australia in 2009 and 2010.
• Comparative data for IPD has been systematically collected since 2002.

Observation:

• In 2009, 1,556 IPD cases were reported (7.2/100,000 population); in 2010, 1,640 cases were reported (7.4/100,000).
• Indigenous Australians experienced IPD rates nearly six times higher than non-Indigenous Australians in both years.
• IPD rates caused by serotypes in the 7-valent pneumococcal conjugate vaccine (7vPCV) decreased across all age groups.
• IPD rates caused by non-7vPCV serotypes increased in Indigenous and non-Indigenous children under 5.
• In Indigenous adults aged 50 and over, IPD rates caused by both 23-valent pneumococcal polysaccharide vaccine (23vPPV) and non-23vPPV serotypes showed an overall increase, particularly in 2010.

Findings:

• There were 110 IPD-attributed deaths in 2009 and 137 in 2010, with potential under-reporting.
• Reduced penicillin susceptibility in invasive pneumococcal isolates remained low.
• Reduced susceptibility to third-generation cephalosporins was rare.

Implications:

• The findings highlight persistent health disparities in IPD burden among Indigenous Australians.
• The shift towards non-vaccine-serotype IPD in young children warrants further investigation and potential vaccine strategy adjustments.
• Increasing IPD rates in older Indigenous adults underscore the need for targeted public health interventions and vaccination strategies.