Economic evaluation of pneumococcal conjugate vaccination in The Gambia

Abstract

BackgroundGambia 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.MethodsWe 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.ResultsAssuming 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.ConclusionsBased 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.

Cost–effectiveness models of pneumococcal conjugate vaccines: variability and impact of modeling assumptions

“…This article was the same for both searches and was included in the review [7]. In total, 16 articles were included in the final analysis (Table 1) [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…One study included nine-valent PCV (an unmarketed vaccine [20]), two compared PCV10 with PCV7 [8,13], and one compared PCV13 with PCV7 [11]. Seven were cohort-based models [15][16][17][18][19][20][21], nine studies used some variation of a population-based model [7][8][9][10][11][12][13][14]22], and most were from the healthcare perspective (Table 1).…”

“…The epidemiologic data used in the analyses, specifically serotype coverage, and disease incidence, were variable across studies (Table 2) [3,5,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26]. Serotype coverage was either taken from a time period prior to widespread PCV7 use or the most current serotype coverage data were utilized.…”

“…All models including PCV10 and PCV13 apply the selected value to the extent of serotype coverage in the newer vaccines to account for the impact of broader serotype coverage. Overall, 15 of 16 papers only included invasive disease caused by S. pneumoniae [7][8][9][10][11][12][13][14][15][16][17][19][20][21][22], whereas Knerer et al also included invasive disease caused by NTHi [18]. In this analysis, the efficacy of PCV10 against NTHi invasive disease was assumed to be equivalent to the efficacy against AOM caused by NTHi, estimated from the POET study using PCV11 [5,18].…”

Cost-effectiveness analysis of 10- and 13-valent pneumococcal conjugate vaccines in Peru

“…In a report from Sweden and Denmark [60], a study from Greece, Germany and the Netherlands [61], and another from Gambia [62], PCV13 prevented more cases of IPD and deaths and gained more quality adjusted Life Years (QALYs) than PCV10. The same results were observed in Canada, which had a 2 + 1 PCV schedule like that of Peru [63].…”