Table 3

Rates of hospitalisation for acute respiratory disease, Sydney children under 18 years of age, 1994–2001, by age and study period, using Method 2 with periseasonal baseline*

Age group	Population at risk†	Number of hospitalisations		Mean weekly rate			Annual rate attributable to influenza (95% CI)‡
		Number of hospitalisations		Rate/100 000 population‡
		Influenza predominant period	Baseline period	Influenza predominant period	Baseline period	Excess attributable to influenza
*As per previous study.²
†Australian Bureau of Statistics mid-year estimate for 1998.
‡Rates and CIs rounded to whole numbers.
<1 y	55972	3015	1829	206	160	45	153 (126 to 180)
1 to <2 y	54566	2538	1660	171	144	27	92 (73 to 111)
2 to <5 y	161989	4427	3342	102	99	3	10 (0 to 26)
5 to <10 y	268358	3197	2514	45	45	0	2 (0 to 12)
10 to <18 y	417458	2840	2051	25	23	2	6 (0 to 19)