Table 2. Key issues considered in economic evaluations of seasonal influenza vaccination.

				Key issues relating to outcomes*
Paper	Target group	Number of studies reviewed	Main study conclusions	Herd	Endp	Prod	VCost	VEff	Other key issues
Newall 201217	Children ≤ 18 y	20	11/20 cost saving; remainder mostly cost-effective	√	√	√	√		Difficulty estimating severe outcomes.
Coleman 200646	Children	7	Not discussed	√		√			Consumer choice Direct expenses paid by households Trade-off between paying for prevention and treatment
Nichol 201147	Children ≤ 18 y	20	11/20 cost saving; remainder mostly cost-effective	√
Savidan 200848	Children < 18 y	15	All cost saving or cost-effective	√			√	√
Burls 200652	Healthy adults, healthcare workers	14	10/14 cost saving (including 2/2 on health care workers)	√
Gatwood 201249	Healthy adults 18–64 y	7	“Generally not cost saving”			√		√	Variability in outcomes Setting of vaccine delivery Severe adverse events Estimating less severe endpoints
Hogan 201250	Healthy adults	10	8/10 favored vaccination	√	√		√	√	Perspective (employer only or employee as well)
Newall 200951	Adults 50–64 y	6	All cost-effective		√	√	√	√	Life expectancy in people with co-morbidities
De Waure 201245	Adults > 50 y and high-risk populations	20	All cost saving or cost-effective in both elderly and high-risk groups	√		√
Postma 200653	Elderly	18	15/18 cost saving, 16/18 cost-effective			√	√	√	Definition of influenza-attributable hospitalisation or death

^* Herd: herd protection; Endpt: mismatch in endpoints used to estimate incidence and vaccine effectiveness (e.g., acute respiratory illness, influenza-like illness, laboratory-confirmed influenza); Prod: productivity loss due to influenza; VCost: drivers of vaccination costs (purchase and administration); VEff: drivers of vaccine effectiveness.