Invasive pneumococcal disease in Indigenous people in north Queensland, 1999-2004

OBJECTIVE: To describe the epidemiology of invasive pneumococcal disease (IPD), and the impact of pneumococcal vaccines on IPD, in Indigenous people in north Queensland. SETTING: North Queensland, 1999-2004; there are about 53 750 Indigenous people in the region, including nearly 6900 children < 5 years and nearly 5650 adults > or = 50 years. MAIN OUTCOME MEASURES: Incidences of IPD in Indigenous children and in Indigenous adults compared between the 3 years before and after the introduction of a 7-valent pneumococcal conjugate vaccine (7vPCV) (1999-2001 versus 2002-2004). RESULTS: Estimated annual incidence of IPD in Indigenous children < 5 years of age declined from 170 to 78 cases per 100 000 in the 3 years following the introduction of 7vPCV in 2001. The annual incidence of vaccine-preventable IPD in Indigenous adults had declined by 86% since a 23-valent pneumococcal polysaccharide vaccine (23vPPV) was introduced to the region in 1996, to 15 cases per 100 000 (95% CI, 8-25) in 2002-2004. CONCLUSION: Although there was a rapid decline in IPD in young Indigenous children, it is unlikely that the incidence will fall much further with the current 7-valent vaccine. There was a suggestion that vaccinating Indigenous children indirectly protected those aged 5-14 years and Indigenous adults > or =15 years of age. Incidence of IPD in Indigenous adults in 2002-2004 was the lowest on record in the region.