Table 4. Clinical Presentation of Influenza B Patients According to Age Group and Virus Lineage (Victoria versus Yamagata).

The IBVD (Influenza B in Vircases database) Study, France, 2003–2004 to 2012–2013.

	0–4 years		5–14 years		15–64 years		>65 years
	B Yamagata	B Victoria	B Yamagata	B Victoria	B Yamagata	B Victoria	B Yamagata	B Victoria
	(n = 318)	(n = 136)	(n = 415)	(n = 397)	(n = 488)	(n = 232)	(n = 36)	(n = 13)
Gender ratio	1.0	1.0	1.2	1.4	1.0	1.0	0.9	0.7
% of patients with 7 symptoms or more	21.4%	22.8%	41.2%	48.7% *	65.7%	64.2%	50.0%	53.9%
Symptoms (%) ( a )
Fever	99.7%	100.0%	99.0%	98.5%	96.3%	97.0%	94.4%	100.0%
Asthenia	58.2%	64.7%	78.0%	77.6%	90.1%	88.8%	88.9%	69.2%
Myalgia	24.6%	28.7%	52.7%	57.9%	90.3%	87.5%	83.3%	92.3%
Shivering	31.8%	33.1%	59.6%	64.8%	83.2%	78.3%	80.6%	61.5%
Cephalalgia	26.2%	34.6%	71.7%	80.6% **	79.5%	81.5%	74.3%	84.6%
Cough	80.3%	82.4%	81.1%	84.9%	88.8%	90.1%	97.1%	92.3%
Expectoration	6.8%	12.5% *	10.0%	12.9%	23.3%	17.3%	32.4%	38.5%
Bronchitis/bronchiolitis	3.2%	4.4%	3.0%	4.3%	8.5%	6.1%	17.6%	23.1%
Rhinitis	77.5%	75.7%	65.9%	77.3% **	76.0%	75.8%	71.4%	61.5%
Pharyngitis	54.1%	52.9%	52.4%	61.5% **	65.0%	71.2%	37.1%	61.5%
Otitis/earache	14.7%	11.8%	6.5%	5.3%	9.9%	5.2% *	0.0%	0.0%
Gastrointestinal symptoms	19.9%	11.0% *	24.0%	21.4%	14.5%	17.2%	18.2%	15.4%
Conjunctivitis	10.6%	12.1%	8.1%	12.0%	11.1%	10.8%	0.0%	16.7% *
Adenopathy	10.6%	12.1%	15.1%	12.7%	7.0%	10.3%	4.0%	0.0%

^a Sudden onset of symptoms is not presented as included in the ARI case definition; dyspnoea is not presented as only collected since the 2009–2010 season.

p-value for the comparison with influenza B patients of the same age group:

* <0.05

**<0.01