Table 4.

Components and main findings of typhoid vaccine economic evaluations.

	First author, year, reference	Analytical approach	Economic perspective	Setting	Burden of disease	Costs	Vaccine intervention modelled	Vaccine effectiveness
1	Musgrove 1992 [32]	CBA CEA	Public sector	PAHO SIREVA countries	150 cases per year per 100k population. CFR1% Does not cost pain, suffering or death.	Vaccine programs and clinical/field trials or pilots.	Mass vaccination; reducing number of doses over time.	Estimated 90%
2	Shepard 1995 [33]	CUA, cost per QALY	Public sector costs; societal benefit captured as QALYs	Countries with middle, high or very high U5MR	1.5 cases per person per lifetime. CFR 1.8% Morbidity is excluded from QALY estimates	Marginal costs of additional vaccination within a childhood programme	By birth cohort, two doses	Anticipated 80% over 10 y
3	Poulos 2004 [31]	CBA	Multi-dimensional public sector and societal	Kalkaji slum, New Delhi, India	As per [35]. Does not cost pain, suffering or death.	As above. Public funded vaccine programme.	Campaign with 80% coverage of: age 2–5, age 6–19, or all-age.	70% for 3 years
4	Canh 2006 [29]	WTP, contingent valuation, CBA	Private	Hue, Vietnam	Raised incidence 1995–9; associated with outbreak in 1996 Benefits measured by WTP.	Proposed USD 0.67 1.70 3.30 6.70 13.30	N/A	Proposed: 70%, 3 y; 70%, 20 y; 99%, 3 y; 99%, 20 y
5	Cook 2008 [30]	CUA	Public sector and societal	Kolkata, India; Karachi, Pakistan; North Jakarta, Indonesia; Hue, Vietnam	Highest in the sites within Karachi and Kolkata, lowest in Hue. Reported incidence double to account for false negative blood cultures. DALY weight 0.27, illness duration 7d CFR 1%.	Private direct and indirect cost of illness obtained in interviews with confirmed cases, public costs obtained from health facilities. Public and private vaccination costs from literature and estimation.	Campaigns: 1. School children 5 to 14 y 2. Children aged 2–15 y All 2 y+	65%, 3 y
6	Cook 2009 [28]	CBA total economic benefits vs costs 1. Societal COI 2. Above + Value of statistical life (VSL) saved 3. WTP (contingent valuation) + public costs	Societal	Tiljala and Narkeldanga slums, Kolkata, India	3.4 case per 1000 2–4 y 4.9 per 1000 5–15 y 1.2 per 1000 16 y+ DALY weight 0.27 CFR 1%	Total marginal vaccine cost USD (2007) $1.11 WTP as per [36] VSL from literature.	Campaigns: 1. School children 5–14 y 2. Children aged 2–15 y All 2 y+	65%, 3 y
7	Lauria 2009 [27]	Optimisation model: different adult and child pricing, implicit CEA	Public sector	Hypothetical population	3.5 annual cases per 1000 children and 1 per 1000 adults	As per [38]	Price-dependent uptake	70%, 3 y

	First author, year, reference	Time horizon	Discounting	Disease dynamics	Sensitivity analysis	Data source(s)	Findings
1	Musgrove 1992 [32]	14 and 24 years	10% pa	No	Program administration costs, vaccine costs, delay between accrual of costs and benefits	Expert opinion	Describes incidence, treatment costs and vaccination costs at which a program would be cost-neutral
2	Shepard 1995 [33]	10 years	3%, costs and benefits	No. Steady states pre-and post- vaccine program start. Assumes disease most common in late childhood or early adulthood.	1. Dose cost at USD50/QALY. 2. Vaccine development costs.	Expert opinion; extrapolation of high incidence epidemiological studies [34]	Preliminary estimate of highly CE (<USD50 per QALY, 1992 price) if data assumptions are valid. Critical parameters are incidence, CFR, VE, vaccine costs
3	Poulos 2004 [31]	3 years	10%	No	Incidence; vaccine cost; ratio of total economic benefit to measured COI	Bahl 2004 [35]	Immunisation of 2-5 year olds is cost saving to the public sector in a high incidence setting. Sensitivity analysis and inclusion of private costs suggest vaccination of other ages may also be highly CE.
4	Canh 2006 [29]	N/A	Inherent	Typhoid perceived to be in decline by 67% of participants	N/A	Cross sectional survey in 2002 of households with children	Survey participants are more sensitive to price than to expected vaccine efficacy or duration of protection. Modest user fees could support a vaccination programme.
5	Cook 2008 [30]	Over duration of vaccine	3%	No	Single parameters and Monte Carlo across all parameters, triangular distribution. VE 55% to 75%, duration 2–4 y,vaccine cost USD 0.40–0.80 (2007 prices), delivery cost variable. CFR 0.5–3%, illness duration 4 d to 3w, DALY weight 0.08–0.47.	DOMI	No programmes would be cost saving but (school-) child immunisation would be very CE to health services or society in all but Hue, including under sensitivity analysis. Adult vaccination in Kolkata and N. Jakarta is less CE but still meet thresholds. Surveillance likely reduced illness costs through early diagnosis.
6	Cook 2009 [28]	1 year cost, 3 year benefits	3%	No	As per [30]. VSL varied by 50%	Kolkata [37]	Economic perspective 1 is not cost neutral, but perspectives 2 and 3 indicate benefits greater than cost across all campaign strategies. Sensitivity analyses suggest WTP and VSL models show net benefit for all campaign strategies across most parameter sets.
7	Lauria 2009 [27]	3 y	8%	Possible herd protection described in a sensitivity analysis, with variable adult and child transmissibility.	Monte Carlo simulation, allowing most parameters to vary.	Five Asian countries [37]	There is minimal advantage to different vaccination charges for children and adults under the static model. Herd protection greatly influences case numbers and value.

CBA, cost-benefit analysis; CE, cost-effective(ness); CEA, cost-effectiveness analysis; CFR, case-fatality rate (proportion of cases that result in death); CUA, cost-utility analysis; COI, cost of illness; DALY, Disability adjusted life-year; DALY weight, a scale from 0 (perfect health) to 1 (death). DOMI, Diseases of the most impoverished programme [39]; PAHO, Pan-American Health Organization; SIREVA, Sistema Regional de Vacunas (Regional Vaccine System); U5MR, under-five mortality rate; USD, United States Dollars; VE, vaccine effectiveness; WTP, willingness to pay.