Table 5.

Components and main findings of cost of illness studies and willingness to pay studies used in typhoid vaccine economic evaluations.

	First author, year, reference	Analytical approach	Economic perspective	Setting	Burden of disease	Costs	Vaccine intervention modelled	Vaccine effectiveness
1	Bahl 2004 [35]	Cost of illness	Multidimensional public sector and societal costs	Kalkaji slum, New Delhi, India	Culture confirmed incidence per year: 17 per 1000 under 5s; 12 per 1000 5–18 y; 1 per 1000 >19 y	Public sector/institutional and private costs, comprising direct medical, direct non-medical and indirect costs; for hospitalised and non-hospitalised	N/A	N/A
2	Poulos 2011 [38]	COI	Public and private (direct and indirect)	Hechi, China; North Jakarta, Indonesia; Kolkata, India; Karachi, Pakistan; Hue, Vietnam.	Highest in the sites within Karachi and Kolkata, lowest in Hechi and Hue.	Measured by questionnaire, with estimates for nonmarket activities. Karachi costs from expert information.	N/A	N/A
3	Whittington 2009 [36]	WTP	Private	Tiljala slum and Beliaghata neighbourhood, Kolkata, Inida	2 case per 1000 population per year, peak incidence in older children and teenagers	Proposed USD (2007) 0.22 0.56 1.11 11.11 And sliding scale.	Price-dependent uptake	70%, 3 y

	First author, year, reference	Time horizon	Discounting	Disease dynamics	Sensitivity analysis	Data source(s)	Findings
1	Bahl 2004 [35]	One year surveillance	N/A	No. Decline in incidence rate with age is informative of an immunising infection.	With both most conservative and least conservative cost estimates, and with incidence both on confirmed and clinically suspected disease.	Cohort study 1995–6, weekly interviews and passive surveillance.	Costs are high per episode regardless of age, both private and public/institutional. Hospitalisation and non-response to antimicrobials increase costs
2	Poulos 2011 [38]	N/A Interviews at 7, 14 and 90 d from disease onset.	N/A	N/A	N/A	Interviews with cases or carers.	Total episode costs range from USD 15–132. Private costs exceed public costs unless reimbursed. Hospitalisation adds to costs substantially. 14 to 49% of households borrowed money to pay for treatment. Costs of drug resistant infection are higher, but not significantly so.
3	Whittington 2009 [36]	N/A	Inherent	N/A	N/A	Cross sectional survey of households with children.	9% would decline a vaccine, with a further 7% only accepting free vaccine. WTP is at least USD2. Vaccines for children were valued higher than those for adults. Time to think reduces willingness to purchase vaccine.