Table 3. Sensitivity and specificity of symptom and sign combinations for the identification of 2009 influenza A virus (H1N1) infection.

Symptoms and signs		non-influenza illness vs.2009 influenza A virus (H1N1) infection
		children		adults
		Sensitivity (%)	Specificity (%)	Sensitivity (%)	Specificity (%)
Single symptom or sign	Fever	99	6	88	23
	Cough	95	20	85	46
	Coryza	71	34	33	67
	Sore throat	58	82	65	54
	Any respiratory symptom	98	13	96	24
	Headache	43	85	23	81
	Malaise	23	94	30	80
	Myalgia	59	80	61	52
	Any constitutional symptom	78	69	83	40
Symptom and sign combinations	Fever + cough	94	23	74	59
	Any respiratory + any constitutional symptom	77	74	79	56
	Fever + any respiratory symptom	97	17	84	43
	Fever + any constitutional symptom	77	73	76	53
	Cough + any constitutional symptom	74	78	70	71
	Influenza-like illness	76	77	72	65
Rapid influenza diagnostic test		57	100	38	100