Invasive pneumococcal disease in Australia, 2001.

Area of Science:

• Epidemiology
• Infectious Diseases
• Public Health

Background:

• In 2001, Australia recorded 1,681 invasive pneumococcal disease (IPD) cases, with notification rates varying geographically.
• Pneumococcal disease predominantly affected children under 5 years old, with significantly higher rates in Indigenous Australians, particularly in the Northern Territory.

Purpose of the Study:

• To present the first national data on invasive pneumococcal disease (IPD) in Australia.
• To analyze IPD epidemiology, clinical presentations, risk factors, serotype distribution, and antibiotic susceptibility.
• To inform the evaluation of the newly introduced conjugate vaccine and guide future pneumococcal vaccination strategies.

Main Methods:

• National surveillance data from the National Notifiable Diseases Surveillance System (NNDSS) for 2001.
• Enhanced surveillance in selected states and territories covering 72% of the population.
• Analysis of clinical presentations, risk factors, serotypes, and antibiotic susceptibility of IPD isolates.

Main Results:

• IPD notification rate was 8.6 per 100,000 population, highest in northern regions and Indigenous children (up to 483 per 100,000).
• Pneumonia (56%) and bacteraemia (36%) were the most common clinical presentations; overall case fatality rate was 8.6%.
• Serotype coverage by the 7-valent vaccine was lower in Indigenous children (55%) compared to non-Indigenous children (86%); reduced susceptibility to penicillin and cephalosporins was observed.

Conclusions:

• IPD surveillance data highlights significant health disparities for Indigenous Australians and children.
• The findings underscore the need for targeted vaccination strategies and ongoing monitoring of antibiotic resistance.
• These national data are crucial for assessing the impact of pneumococcal conjugate vaccines and refining public health interventions.