Table 1. Number of cases and incidence of meningococcal disease in Italy by epidemiological year.

		2008/09		2009/10		2010/11		2011/12		2012/13		Total
Italy		N	%	N	%	N	%	N	%	N	%	N	%
	Known serogroup	170	85.4	109	75.2	121	78.6	107	72.8	102	68.5	609	76.7
	Unknown serogroup	29	14.6	36	24.8	33	21.4	40	27.2	47	31.5	185	23.3
	Total cases	199		145		154		147		149		794
	Population	59832179		60192698		60483385		60010325		60010325		300528911
	Incidence	0.33		0.24		0.25		0.24		0.25		0.26
Regions with <20% of cases with unknown serogroup		N	%	N	%	N	%	N	%	N	%	N	%
	Known serogroup	123	93.9	79	82.3	69	87.3	76	85.4	80	83.3	427	87.0
	Unknown serogroup	8	6.1	17	17.7	10	12.7	13	14.6	16	16.7	64	13.0
	Total cases	131		96		79		89		96		491
	Population	26901733		27131868		27317071		27118025		27118025		135586720
	Incidence	0.49		0.35		0.29		0.33		0.35		0.36
Regions with ≥20% of cases with unknown serogroup		N	%	N	%	N	%	N	%	N	%	N	%
	Known serogroup	47	69.1	30	61.2	52	69.3	31	53.4	22	41.5	182	60.1
	Unknown serogroup	21	30.9	19	38.8	23	30.7	27	46.6	31	58.5	121	39.9
	Total cases	68		49		75		58		53		303
	Population	32930447		33060830		33166315		32892300		32892300		164942191
	Incidence	0.21		0.15		0.23		0.18		0.16		0.18