Table 2.

Influenza case distribution by age groups and viral subtype in Canada.

Year†	<5 years	5–9 years	10–14 years	15–24 years	25–44 years	45–64 years	65+ years	Age unknown
1999/00 (N = 5,907)‡	16.2%	3.4%	1.9%	4.4%	12.9%	14.8%	42.2%	4.1%
2000/01 (N = 3,935)‡	24.0%	13.0%	8.0%	16.0%	21.0%	8.0%	8.0%	2.0%
2001/02 (N = 6,258)‡	28.0%	6.0%	8.0%	9.0%	11.0%	8.0%	27.0%	3.0%
2002/03 (N = 2,953)‡	NR	NR	NR	NR	NR	NR	NR	NR
2003/04 (N = 7,708)‡	33.0%	5.0%	5.0%	11.0%	11.0%	9.0%	25.0%	1.0%
2004/05 (N = 10,006)
Influenza A (n = 8,567)	11.0%	3.0%	3.0%	5.0%	12.0%	13.0%	51.0%	2.0%
Influenza B (n = 1,439)	18.0%	12.0%	5.0%	7.0%	19.0%	13.0%	22.0%	4.0%
2005/06 (N = 6,590)
Influenza A (n = 4,028)	23.0%	9.0%	5.0%	8.0%	18.0%	12.0%	25.0%	0.0%
Influenza B (n = 2,562)	22.0%	20.0%	19.0%	20.0%	9.0%	6.0%	4.0%	0.0%
2006/07 (N = 7,023)
Influenza A (n = 6,051)	23.0%	11.0%	7.0%	5.0%	22.0%	11.0%	20.0%	2.0%
Influenza B (n = 972)	19.0%	10.0%	3.0%	0.0%	24.0%	21.0%	23.0%	0.0%
2007/08 (N = 10,187)
Influenza A (n = 5,760)	24.0%	6.0%	4.0%	11.0%	22.0%	14.0%	19.0%	0.0%
Influenza B (n = 4,427)	17.0%	11.0%	4.0%	4.0%	21.0%	17.0%	26.0%	0.0%
2008/09 (N = 23,376)‡	16.0%	11.0%	11.0%	18.0%	22.0%	14.0%	8.0%	0.0%
2009/10 (N = 39,042)‡	16.0%	14.0%	12.0%	17.0%	21.0%	16.0%	4.0%	0.0%
2012/13* (N = 23,293)		5–19 years		20–44 years
Influenza A (n = 20,262)	13.1%	7.2%		15.5%		17.0%	47.3%	0.0%
Influenza B (n = 3,031)	20.4%	26.2%		16.9%		16.8%	19.7%	0.0%

Note: NR, not reported; Data obtained from The Canadian FluWatch surveillance system unless otherwise indicated.^11-19

^†Data were not available in the available FluWatch cumulative weekly reports for 2010/11, 2011/12 and 2012/13 seasons.

^‡Data by viral subtype were not available.

^*Data were obtained from NACI statement on seasonal influenza vaccine for 2013/14.²³