Selected country: NIGER < change/back to search

Explore the key typhoid vaccination cost-effectiveness results as well as the specific inputs and outputs of the analysis for Niger below.

Expand the "Parameters" box to explore the influence of different inputs. For example, MDR/XDR typhoid may require more expensive treatment, and therefore the prevalence of antimicrobial resistant (AMR) typhoid could impact on TCV cost-effectiveness. This is one of the parameters that can be updated below based on local insight.

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Cost-effectiveness Results

Which strategy is likely to be the most cost-effective (i.e. optimal), given current evidence?

Willingness to pay :

$2000

At a willingness-to-pay threshold of $ per DALY averted, the optimal strategy in terms of cost-effectiveness is with a certainty of %.

Cost-effectiveness acceptability frontier

Solid line presents the results using the default input parameters. Dashed line presents the results using a subset of input parameter values (see below).

The graph above displays what is called the cost-effectiveness acceptability frontier (CEAF). This plot answers two questions:

What is the optimal strategy in terms of cost-effectiveness given the currently available evidence? This is shown by the color of the line at a given willingness-to-pay value.
How certain are we about the optimal strategy? This is shown by the probability on the Y-axis, again for a given willingness-to-pay value.

Parameters + expand

These are some of the key inputs of the cost-effectiveness model that determine whether vaccination with TCV would be a cost-effective intervention for Niger. By default, the full range of the inputs that are most likely based on current research are used, but you can explore the effects of limiting the range of values by toggling the min and max value for each parameter.

Make sure to press the APPLY bottom to get results with your chosen range of input parameter(s). For more information on the input parameters, click on the tab 'KEY INPUT PARAMETER' on top of this page.

Typhoid incidence:

165.74

555.78

Typhoid case fatality rate:

0.52

Probability of hospitalization:

0.74

% of deaths occurring in hospital:

25%

100%

% antimicrobial resistant (AMR) strain:

100%

Relative burden of AMR:

Treatment cost, inpatient:

$0.9

$366.95

Treatment cost, outpatient:

$0.01

$4.82

Vaccine delivery cost, routine:

$1.81

$7.84

Vaccine delivery cost, campaign:

$1.83

$2.64

Mean age of typhoid infection (years):

3.4

17.31

Warning: Results are based on only a sample of the possible parameter values.

Simulations:

Cost-effectiveness acceptability curves + expand

The graph below displays what is called the cost-effectiveness acceptability curves (CEACs) for each strategy - no vaccination, routine vaccination only, routine vaccination plus a catch-up campaign up to 5 years of age, and routine vaccination plus a catch-up campaign up to 15 years of age. The CEACs show the probability of each strategy having the highest net benefit (Y-axis) - in other words, the probability that it's the optimal, most cost-effective strategy - over a range of willingness-to-pay values (X-axis) for the cost to avert one disability-adjusted life-year (DALY) lost due to typhoid illness or death. The strategy with the highest probability value for a WTP value, is not necessarily the optimal strategy given current evidence.

Results are based on 2000 samples. Costs are presented in USD2016. DALY = disability-adjusted life-year.

Solid line presents the results using the default input parameters. Dashed line presents the results using a subset of input parameter values (see above).

Cost-effectiveness plane (note: this plot takes some time to appear) + expand

The graph below displays the cost-effectiveness plane, which shows the estimated incremental costs (cost of vaccination minus typhoid treatment costs averted, Y-axis) and the disability-adjusted life-years averted (X-axis) for 2,000 parameters samples for each of the three vaccination strategies - routine vaccination only, routine vaccination plus a catch-up campaign up to 5 years of age, and routine vaccination plus a catch-up campaign up to 15 years of age - compared to no vaccination. For mean estimates of total costs and disease and economic burden averted for each of three vaccination strategies, see tab 'Total costs and Impact'. Plot shows the results based on the subset of input parameter values selected above.

Costs are presented in USD2016. DALY = disability-adjusted life-year.

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Key Input Parameters

These tables show the key input parameters used by the cost-effectiveness model to determine the optimal typhoid vaccination strategy for Niger. Input parameters informed by country-specific evidence are denoted as 'country-specific', input parameters assumed the same for all countries are denoted as 'common'. Parameters are divided into three categories: disease-related, vaccine-related, and demographic. Click on the name of each parameter to learn more. The Appendix of our paper details how each of the parameters was estimated based on the available evidence.

Disease-related characteristics

	Mean	95% confidence interval	Uncertainty distribution	Common/country-specific
Typhoid incidence (per 100,000 persons per year) The incidence of symptomatic typhoid fever cases in the community. The range is informed by estimates from Antillon et al (2016) and the Global Burden of Disease study. The "crude" incidence of blood-culture confirmed typhoid fever detected by passive surveillance will typically be lower.	333.05	[187.87-498]	Uniform	Country-specific
Age of typhoid cases (and deaths) We assume that the average age of death from typhoid fever is the same as the average age of cases, since case fatality rates do not by age (see Pieters et al, 2018).	10.91	[5.87-15.51]	Uniform	Country-specific
Probability of hospitalization Probability that a symptomatic typhoid fever case in the community will be hospitalized. Based on Mogasale et al (2016) and/or country-specific studies.	0.07	[0-0.31]	Beta	(varies)
Case fatality rate among hospitalized individuals Based on Pieters et al (2018) and/or country-specific studies.	0.06	[0.01-0.2]	Beta	(varies)
Percent of deaths occurring outside of hospital Based on assumption. Deaths occurring outside of hospitals are difficult to detect and attribute to typhoid fever.	0.63	[0.28-0.98]	Uniform	Common
Percent of typhoid cases that are antimicrobial resistant The prevalence of antimicrobial resistance (AMR) varies over time and from country to country.	0.51	[0.03-0.98]	Uniform	Common
Burden of antimicrobial resistant (AMR) cases compared to sensitive cases "Multiplication factor applied to average treatment cost, average years of life lived with disability, and average probabilty of death for AMR cases.	1.98	[1.05-2.93]	Uniform	Common
Treatment cost, inpatients Calculated based on cost per bed-day times length of stay in hospital, cost of lab tests, costs of drugs, and cost of prior outpatient visit (see Bilcke et al, 2019, Appendix 2.2.6); or country-specific data.	31.99	[5.08-93.92]	Uniform	Country-specific
Treatment cost, outpatients Based on WHO-CHOICE 2010 unit cost for outpatient visit (for any disease), multiplied by an adjustment factor of 0.63 based on validation exercise (see Bilcke et al, 2019, Appendix 2.2.6); or country-specific data.	1.2	[0.16-2.82]		Country-specific
Treatment cost, patients not seeking formal care Assumed to be equal to cost of drugs for outpatient.	0.83	[0.03-2.33]		Country-specific
Probability of seeking health care Probability that symptomatic typhoid case in the community will seek any health care. Based on relative incidence estimates for passive versus active typhoid surveillance studies (see Antillon et al, 2017).	0.58	[0.41-0.77]		Common
Number of visits to a medical doctor We assume that each typhoid patient only seeks medical care once during course of illness (conservative assumption).	1		Beta	Common
Length of stay in hospital (days) Based on country-specific data or random effects meta-analysis (for countries without data).	5.7	[3.15-8.95]	Fixed	Country-specific
Duration of illness, inpatients and outpatients (years) Based on random effects meta-analysis of typhoid cost of illness studies.	0.04	[0.03-0.05]		Common
Relative duration of illness for cases not seeking care We assume that cases who do not seek care have a duration of illness that is on average half that of those who do seek care.	0.49	[0.03-0.98]	Gamma	Common
Disability weight Used to calculate disability-adjusted life-years (DALYs); weighted average of disability weights for mild, moderate, and severe acute infectious disease episodes (see Bilcke et al, 2019, Appendix 2.2.8).	0.09	[0.06-0.12]	Uniform	Common

Vaccine-related characteristics

	Mean	95% confidence interval	Uncertainty distribution	Common/country-specific
Vaccine procurement cost Full cost per dose of vaccine. Gavi will subsidize a proportion of the total cost depending on each country's transition phase. Based on Bharat price announcement and personal communications with Gavi.	1.5	[1.5-1.5]		Common
Vaccine delivery cost, routine doses Based on EPIC and other studies measuring cost of delivery for other vaccines (see Bilcke et al, 2019, Appendix 2.2.7). Gavi will subsidize a proportion of the total cost depending on each country's transition phase.	3.44	[2.09-5.74]	Fixed	Country-specific
Vaccine delivery cost, campaign doses Based on EPIC and other studies measuring cost of delivery for other vaccines (see Bilcke et al, 2019, Appendix 2.2.7).	2.13	[1.96-2.34]		Country-specific
Injection and safety equipment cost Based on costs of vaccine programs across 94 low- and middle-income countries (see Portnoy et al, 2015).	0.23	[0.21-0.24]		Common
Number of years start-up costs are incurred We assume that start-up costs are incurred over 1-3 years, with equal probability assigned to 1, 2, and 3 years.	1.97	[1-3]	Gamma	Common
Percent of delivery cost on-going, routine doses Based on EPIC and other studies measuring cost of delivery for other vaccines (see Bilcke et al, 2019, Appendix 2.2.7).	0.64	[0.49-0.79]	Multinomial	Country-specific
Vaccine coverage, routine immunization Based on Gavi's demand forecast for TCV introduction between 2019 and 2030 (see Bilcke et al, 2019, Appendix 2.1.5).	0.8			Country-specific
Vaccine coverage, catch-up campaign Based on Gavi's demand forecast for TCV introduction between 2019 and 2030 (see Bilcke et al, 2019, Appendix 2.1.5).	0.7			Country-specific
Initial efficacy of TCV Vaccine efficacy (direct protection) immediately following immune response to vaccination. Based on efficacy of TCV against clinically-relevant endpoint in human challenge model (Jin et al, 2017) and seroefficacy (Voysey and Pollard, 2018).	0.88	[0.8-0.95]		Common
Duration of vaccine-induced immunity We assume exponential waning of vaccine-induced immunity. Estimated duration in based on an analyis of data for the Vi-rEPA typhoid conjugate vaccine (see Bilcke et al, 2019, Appendix 2.1.3).	72.26	[3.73-234.52]	Uniform	Common

Demographic parameters

	Mean	Uncertainty distribution	Common/country-specific
Population size, Based on World Population Prospects database estimate for YEAR.	19900000	Uniform	Country-specific
Income category Whether the country is classified as low-income, lower-middle income, or upper-middle income.	low-income		Country-specific
Life expectancy at birth (years) Based on data from the World Bank 2014 (https://data.worldbank.org/indicator/SP.DYN.LE00.IN, latest access May 22 2018).	60.83		Country-specific

Key Drivers of Uncertainty

What additional evidence is most valuable?

It is possible to determine which additional data will result in the greatest reduction in uncertainty about the optimal strategy (in terms of cost-effectiveness) by estimating the "expected value of partially perfect information" (EVPPI). The higher the EVPPI, the more valuable obtaining additional evidence on that parameter is likely to be. The results of this analysis can be found at: https://ceatyphoid.uantwerpen.be/country/36/results/output/16/.

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Total costs and impact

These tables show key output values resulting from the typhoid vaccination cost-effectiveness analysis for Niger based on the input parameters.

What's at stake: Projected disease burden without typhoid vaccination

This table shows the projected number of typhoid cases, deaths, treatment costs, years of life lost (due to premature death) and years of life lived with disability per year in Niger, in the absence of a routine vaccination program with typhoid conjugate vaccine.

Results are based on 2000 samples. Median and 95% credible intervals are presented. Costs presented in USD2016.

	no vaccination
cases (thousands)
deaths
treatment costs (thousands)
years of life lost (thousands)
years of life lived with disability (thousands)

What's to gain: Projected benefits for three different vaccination strategies

This table shows the projected disease burden and treatment costs that could be avoided due to routine vaccination with typhoid conjugate vaccine in Niger with each of three different strategies compared to no vaccination. Results are over a 10-year time horizon and discounted at a rate of 3% per year.

Results based on 2000 samples. Costs presented in USD2016.
* Assuming vaccine price to be US$1.50 (country pays in full)

	Projected number with routine: Median (95% credible interval)	Projected number with routine + campaign up to 5 years: Median (95% credible interval)	Projected number with routine + campaign up to 15 years: Median (95% credible interval)
cases averted (thousands)
deaths averted
treatment costs saved (thousands)
years of life saved (thousands)
years of life with disability averted (thousands)
DALYs averted (thousands)

What it would cost: Projected costs for three different vaccination strategies

This table shows the projected costs of vaccination with typhoid conjugate vaccine in Niger with three different strategies. Results are over a 10-year time horizon and discounted at a rate of 3% per year.

Results based on 2000 samples. Costs presented in USD2016.
* Assuming vaccine price to be US$1.50 (country pays in full)

	Projected number with routine: Median (95% credible interval)	Projected number with routine + campaign up to 5 years: Median (95% credible interval)	Projected number with routine + campaign up to 15 years: Median (95% credible interval)
costs of routine vaccination (thousands)
costs of campaign (thousands)
costs of routine vaccination + campaign (thousands)
net costs (thousands) Costs of vaccination minus treatment costs saved

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* NOTE: For conjecture only; model input adjustments outside of published assumptions are not supported by evidence and any adjusted results- have not been corroborated by the researchers or TyVAC.

NOTE: The background, methods, results and discussion of this analysis are presented in detail in Cost-effectiveness of routine and campaign use of typhoid Vi-conjugate vaccine in Gavi-eligible countries: a modelling study. The content presented here should be considered together with this manuscript. Any changes to inputs away from those considered in the manuscript cannot be cited or referenced as such.