Table 4.

Influenza-related inputs (for type A and type B influenza).

	Age range (years)
	0–4	5–17	18–49	50–64	≥65	Sources
Complicated/uncomplicated influenza distribution (%)
Influenza with LRTCa	2.12	1.02	13.19	17.30	20.94	49,50
Influenza with OM	11.88	3.13	0.79	0.35	0.21	49,50
Uncomplicated influenza	86.01	95.85	86.02	82.35	78.85	Complement of above
Influenza with LRTC: treatment setting distribution (%)
Outpatientb	47.87	35.16	35.95	41.60	72.24	Calculated from Molinari et al.4
ED	0	0	0	0	0	Assumption (no data)
Inpatientc,d	0.82	0.34	1.24	2.84	6.18	49,50
Non-medically attended	51.31	64.50	62.82	55.56	21.58	Complement of above4
Influenza with OM or uncomplicated influenza: treatment setting distribution (%)
Outpatientb	47.87	35.16	35.95	41.60	72.24	Calculated from Molinari et al.4
ED	0	0	0	0	0	Assumption (no data)
Inpatientc,e	0.82	0.34	0.46	0.82	2.21	49,50
Non-medically attended	51.31	64.50	63.59	57.58	25.55	Complement of above4
Inpatient cases resulting in death (%)f	0.28	1.67	2.14	6.94	27.79	Calculated from Molinari et al.4
QALYs lost per case						<18 years;39 ≥18 years calculated
Influenza with LRTC, inpatient	0.076	0.076	0.0115	0.0115	0.0093	from Gold et al.51 and Lee et al.52
Influenza with LRTC, other	0.046	0.046	0.0115	0.0115	0.0093
Influenza with OM, all	0.042	0.042	0.0052	0.0052	0.0036
Uncomplicated influenza, inpatient	0.076	0.076	0.0115	0.0115	0.0093
Uncomplicated influenza, other	0.005	0.005	0.0052	0.0052	0.0036
Medical care costs per case ($)g						4,43
Outpatientb	269	220	307	490	518
Inpatientb	20,831	25,565	33,326	40,890	20,268
Non-medically attended (over-the-counter medication)	4.29	4.29	4.29	4.29	4.29
Patient/caregiver time lost per case (days)						4,53
Outpatient	1.38	1.38	1.15	2.66	5.05
Inpatient	9.13	9.13	13.34	16.63	15.56
Non-medically attended	1.0	0.5	0.5	0.5	1.0

ED, emergency department; LRTC, lower respiratory tract complication; OM, otitis media; QALY, quality-adjusted life year.

^aFor ages 0–17 years, complications rates were based on pneumonia diagnoses only.⁴⁹ For ages ≥18 years, complication rates were based on pneumonia and respiratory diagnoses.⁵⁰

^bWeighted average of high-risk and non-high risk individuals.⁴

^cFor ages 0–17 years, hospitalization rates were based on “any hospitalization” (regardless of complications).⁴⁹

^dFor ages ≥18 years, hospitalization rates were based on pneumonia and respiratory hospitalizations.⁵⁰

^eFor ages ≥18 years, hospitalization rates were based on all-cause hospitalizations minus pneumonia and respiratory hospitalizations.⁵⁰

^fValues were converted from mortality rates among all cases of influenza⁴ to conditional probabilities among inpatient cases of influenza. Deaths among cases that are treated outside the hospital (or not medically attended) were assumed to be negligible.

^gInflated to 2013 US dollars.⁴³