Table 3. Incidence rate ratios (IRRs)^a for pertussis notifications in adolescents aged 12 to 19 years for each year after diphtheria, tetanus and acellular pertussis vaccine programme roll-out, by jurisdictional group, Australia, 2004–2009.

Jurisdictional groupingb	Pre-programme epidemic ratec,d (95% CI)		IRR (95% CI)
			2005	2006	2007	2008	2009
Australian Capital Territory/ South Australia/Victoria	92.6 (87.4–98.0)		0.41 (0.36–0.47)	0.26 (0.23–0.31)	0.20 (0.17–0.24)	0.39 (0.34–0.35)	1.03 (0.93–1.13)
New South Wales	156.8 (150.4–163.4)		0.29 (0.25–0.32)	0.20 (0.17–0.22)	0.13 (0.11–0.15)	1.22 (1.14–1.30)	1.23 (1.15–1.31)
Western Australia	284.2 (263.2–306.9)		0.08 (0.06–0.11)	0.03 (0.02–0.05)	0.01 (0.01–0.03)	0.03 (0.02–0.05)	0.05 (0.04–0.08)
Queensland	134.7 (127.1–142.8)		0.57 (0.50–0.64)	0.36 (0.31–0.42)	0.18 (0.15–0.22)	0.29 (0.25–0.34)	0.95 (0.86–1.05

CI, confidence interval.

^a These represent the ratios given by dividing the notification rate during each of the two epidemic periods after diphtheria, tetanus and acellular pertussis vaccine programme roll-out by the notification rate during the most recent epidemic period before programme roll-out.

^b Jurisdictional groupings were based on programme delivery characteristics.

^c The recent epidemic periods used in the analysis were as follows: Australian Capital Territory, 2003; South Australia, 2001; Victoria, 2001/2002; New South Wales, 2000/2001; Queensland, 2001/2002; Western Australia, 2004; national, 2001.⁶

^d Per 100 000 population.