Economic evaluation of pneumococcal conjugate vaccination in The Gambia.
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We extended the base-case results for PCV9 to estimate the cost-effectiveness of PCV7, PCV10, and PCV13, each compared to no vaccination.Under base-case assumptions ($3.5 per vaccine), compared to no intervention, a PCV9 vaccination program would cost $670 per DALY averted in The Gambia.Assuming a cost-effectiveness threshold of three times GDP per capita, all PCVs examined would be cost-effective at the tentative Advance Market Commitment (AMC) price of $3.5 per dose.
Affiliation: Department of Health Policy and Management, Harvard School of Public Health, Center for Health Decision Science, Boston, MA, USA. sykim@hsph.harvard.edu
ABSTRACT
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Background: Gambia is the second GAVI support-eligible country to introduce the 7-valent pneumococcal conjugate vaccine (PCV7), but a country-specific cost-effectiveness analysis of the vaccine is not available. Our objective was to assess the potential impact of PCVs of different valences in The Gambia. Methods: We synthesized the best available epidemiological and cost data using a state-transition model to simulate the natural histories of various pneumococcal diseases. For the base-case, we estimated incremental cost (in 2005 US dollars) per disability-adjusted life year (DALY) averted under routine vaccination using PCV9 compared to no vaccination. We extended the base-case results for PCV9 to estimate the cost-effectiveness of PCV7, PCV10, and PCV13, each compared to no vaccination. To explore parameter uncertainty, we performed both deterministic and probabilistic sensitivity analyses. We also explored the impact of vaccine efficacy waning, herd immunity, and serotype replacement, as a part of the uncertainty analyses, by assuming alternative scenarios and extrapolating empirical results from different settings. Results: Assuming 90% coverage, a program using a 9-valent PCV (PCV9) would prevent approximately 630 hospitalizations, 40 deaths, and 1000 DALYs, over the first 5 years of life of a birth cohort. Under base-case assumptions ($3.5 per vaccine), compared to no intervention, a PCV9 vaccination program would cost $670 per DALY averted in The Gambia. The corresponding values for PCV7, PCV10, and PCV13 were $910, $670, and $570 per DALY averted, respectively. Sensitivity analyses that explored the implications of the uncertain key parameters showed that model outcomes were most sensitive to vaccine price per dose, discount rate, case-fatality rate of primary endpoint pneumonia, and vaccine efficacy against primary endpoint pneumonia. Conclusions: Based on the information available now, infant PCV vaccination would be expected to reduce pneumococcal diseases caused by S. pneumoniae in The Gambia. Assuming a cost-effectiveness threshold of three times GDP per capita, all PCVs examined would be cost-effective at the tentative Advance Market Commitment (AMC) price of $3.5 per dose. Because the cost-effectiveness of a PCV program could be affected by potential serotype replacement or herd immunity effects that may not be known until after a large scale introduction, type-specific surveillance and iterative evaluation will be critical. Related in: MedlinePlus |
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Mentions: In univariate analyses, results were most sensitive to vaccine price, discount rate, CFR of primary endpoint pneumonia, and vaccine efficacy against primary endpoint pneumonia. Results were moderately sensitive to vaccine wastage rates and vaccination program cost per dose. Results were robust to diagnostic costs, medication costs, outpatient visit costs, wage rates, and transportation costs. When we assumed that vaccine efficacy would be decreased by 15% over a 5-year time horizon, the incremental costs per DALY averted increased to $940, $690, and $590 for PCV7, PCV9 & 10, and PCV13, respectively. When we assumed a 25% decrease in vaccine efficacy up to age 5, the corresponding values for each PCV further increased to $970, $710, and $600. Figure 3 shows a tornadogram summarizing the results of univariate sensitivity analysis using PCV7. Figure 4 presents how cost-effectiveness of each type of PCV varies as the unit price of vaccines are varied up to $10. Using the threshold cost-effectiveness of GDP per capita ($360 in 2005 US$ for 2008), none of the PCVs would be considered very cost-effective at the unit price of $3.5, while all the vaccines would be considered cost-effective under the threshold of three times GDP per capita. |
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Affiliation: Department of Health Policy and Management, Harvard School of Public Health, Center for Health Decision Science, Boston, MA, USA. sykim@hsph.harvard.edu
Background: Gambia is the second GAVI support-eligible country to introduce the 7-valent pneumococcal conjugate vaccine (PCV7), but a country-specific cost-effectiveness analysis of the vaccine is not available. Our objective was to assess the potential impact of PCVs of different valences in The Gambia.
Methods: We synthesized the best available epidemiological and cost data using a state-transition model to simulate the natural histories of various pneumococcal diseases. For the base-case, we estimated incremental cost (in 2005 US dollars) per disability-adjusted life year (DALY) averted under routine vaccination using PCV9 compared to no vaccination. We extended the base-case results for PCV9 to estimate the cost-effectiveness of PCV7, PCV10, and PCV13, each compared to no vaccination. To explore parameter uncertainty, we performed both deterministic and probabilistic sensitivity analyses. We also explored the impact of vaccine efficacy waning, herd immunity, and serotype replacement, as a part of the uncertainty analyses, by assuming alternative scenarios and extrapolating empirical results from different settings.
Results: Assuming 90% coverage, a program using a 9-valent PCV (PCV9) would prevent approximately 630 hospitalizations, 40 deaths, and 1000 DALYs, over the first 5 years of life of a birth cohort. Under base-case assumptions ($3.5 per vaccine), compared to no intervention, a PCV9 vaccination program would cost $670 per DALY averted in The Gambia. The corresponding values for PCV7, PCV10, and PCV13 were $910, $670, and $570 per DALY averted, respectively. Sensitivity analyses that explored the implications of the uncertain key parameters showed that model outcomes were most sensitive to vaccine price per dose, discount rate, case-fatality rate of primary endpoint pneumonia, and vaccine efficacy against primary endpoint pneumonia.
Conclusions: Based on the information available now, infant PCV vaccination would be expected to reduce pneumococcal diseases caused by S. pneumoniae in The Gambia. Assuming a cost-effectiveness threshold of three times GDP per capita, all PCVs examined would be cost-effective at the tentative Advance Market Commitment (AMC) price of $3.5 per dose. Because the cost-effectiveness of a PCV program could be affected by potential serotype replacement or herd immunity effects that may not be known until after a large scale introduction, type-specific surveillance and iterative evaluation will be critical.