Cost–Benefit Analysis of a Mass Vaccination Strategy to Control Brucellosis in Sheep and Goats in Northern Iraq
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Scope and Context
2.2. Economic Model
2.2.1. Data Sources and Model Input Parameters
2.2.2. Model Assumptions and Simplifications
2.2.3. Productivity and Reproduction Impacts
2.2.4. Strategy and Control of the Disease
2.2.5. Sensitivity Analysis
3. Results
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Parameters | Description | Value | Reference/Source |
---|---|---|---|
Annual milk production | litre per adult female (ewe/doe) per year | Pert distribution (Min = 60; Mode = 109; Max = 134) | Pacinovski, et al. [24] |
Fertility rate | Per year, for adult female % | Pert distribution (Min = 0.76; Mode = 0.85; Max = 0.95) | Galal, et al. [25] |
Average price of milk * | Per kg | Pert distribution (Min = 0.6317; Mode = 0.8421; Max = 1.0528) | Questionnaire data |
Average price of a lamb or kid | Per a lamb or kid | Pert distribution (Min = 25; Mode = 50; Max = 75) | Questionnaire data |
Percentage of adult females | Out of the total population | 70.7% | Questionnaire data |
Percentage of lambs/kids | Out of the total population | 26% | Questionnaire data |
Attributable risk | For new (incidence) cases | Pert distribution (Min = 0.05; Mode = 0.25; Max = 0.45) | AlHamada, et al. [17] |
Attributable risk | For existing (prevalence) cases | Pert distribution (Min = 0; Mode = 0.18; Max = 0.34) | AlHamada, et al. [17] |
TP | True prevalence (TP) = | 9.22% | Calculated |
AP | Apparent prevalence (AP) | 8.33% | Alhamada, et al. [13] |
Se | Sensitivity (series testing) | 90.22% | EFSA [20] and Nielsen, et al. [19] |
Sp | Specificity (series testing) | 99.99% | EFSA [20] and Nielsen, et al. [19] |
s | Proportion of susceptible animals [t = 0] | 0.46 | Calculation (s = 1 − TP − Pr) |
Pr | Proportion of protected animals [t = 0] | 0.45 | Calculation (Pr = Vc × Ve) |
Vc | Vaccination coverage | 60% | Directorate of Dohuk Veterinary Hospital |
Ve | Vaccine efficacy | 75% | Benkirane, et al. [26] |
N | Number of adult female sheep and goats in Dohuk Governorate | 706,800 | Total number of animals × percentage of adult females |
P | Number of protected females in Dohuk Governorate (year 0) | 299,115 | Calculated (P = (N × Pr)) |
Re | Effective reproduction number | 1 | assumption of endemic equilibrium |
R0 | Basic reproduction numberR0 = Re ÷ s | 2.18 | Hegazy, et al. [23] |
D | Duration of overall managed breeding before culling | Five years | Calculation (1 ÷ u) |
U | Replacement sheep per year (Cull rate) | 20% | Director of the vet. Services in Dohuk city |
beta | Transmission coefficient | 6.18 × 10−7 | Calculated beta = Re ÷ (N × D × s) |
Rev. 1 vaccine | Price per dose | US$0.10 | Directorate of Dohuk Veterinary in Dohuk city |
Years | Future Benefits | Future Costs | Future Value | PV of Benefits | PV of Costs | NPV |
---|---|---|---|---|---|---|
1 | $0 | $191,200 | −$191,200 | $0 | $179,728 | −$179,728 |
2 | $176,770 | $191,200 | −$14,430 | $156,194 | $168,944 | −$12,750 |
3 | $347,854 | $191,200 | $156,654 | $288,922 | $158,808 | $130,114 |
4 | $499,649 | $191,200 | $308,449 | $390,101 | $149,279 | $240,821 |
5 | $632,108 | $191,200 | $440,908 | $463,907 | $140,322 | $323,584 |
6 | $747,260 | $191,200 | $556,060 | $515,512 | $131,903 | $383,609 |
7 | $847,307 | $191,200 | $656,107 | $549,460 | $123,989 | $425,471 |
8 | $934,257 | $191,200 | $743,057 | $569,494 | $116,550 | $452,944 |
9 | $1,009,865 | $191,200 | $818,665 | $578,647 | $109,557 | $469,091 |
10 | $1,075,649 | $191,200 | $884,449 | $579,361 | $102,983 | $476,377 |
11 | $1,132,914 | $191,200 | $941,714 | $573,592 | $96,804 | $476,788 |
12 | $1,182,789 | $191,200 | $991,589 | $562,913 | $90,996 | $471,917 |
13 | $1,226,245 | $191,200 | $1,035,045 | $548,579 | $85,536 | $463,043 |
14 | $1,264,123 | $191,200 | $1,072,923 | $531,593 | $80,404 | $451,189 |
15 | $1,297,150 | $191,200 | $1,105,950 | $512,753 | $75,580 | $437,173 |
16 | $1,325,955 | $191,200 | $1,134,755 | $492,691 | $71,045 | $421,646 |
17 | $1,351,084 | $191,200 | $1,159,884 | $471,906 | $66,782 | $405,124 |
18 | $1,373,011 | $191,200 | $1,181,811 | $450,791 | $62,775 | $388,016 |
19 | $1,392,148 | $191,200 | $1,200,948 | $429,650 | $59,009 | $370,641 |
20 | $1,408,853 | $191,200 | $1,217,653 | $408,717 | $55,468 | $353,249 |
Total | $19,224,992 | $3,824,000 | $15,400,992 | $9,074,783 | $2,126,463 | $6,948,320 |
Benefits (Median and 95% CI) | |
---|---|
PV Benefits | US$ 13,813,524 (95% CI: −12,964,774–40,290,145) |
PV Costs | US$ 3,241,685 (95% CI: 2,971,912–3,515,547) |
NPV | US$ 10,564,828 (95% CI: −16,203,454–37,049,245) |
BCR | 4.25 (95% CI: −2.71–11.22) |
IRR | 91.38% (95% CI: 11.7–190.6%) |
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Al Hamada, A.; Bruce, M.; Barnes, A.; Habib, I.; D. Robertson, I. Cost–Benefit Analysis of a Mass Vaccination Strategy to Control Brucellosis in Sheep and Goats in Northern Iraq. Vaccines 2021, 9, 878. https://doi.org/10.3390/vaccines9080878
Al Hamada A, Bruce M, Barnes A, Habib I, D. Robertson I. Cost–Benefit Analysis of a Mass Vaccination Strategy to Control Brucellosis in Sheep and Goats in Northern Iraq. Vaccines. 2021; 9(8):878. https://doi.org/10.3390/vaccines9080878
Chicago/Turabian StyleAl Hamada, Ali, Mieghan Bruce, Anne Barnes, Ihab Habib, and Ian D. Robertson. 2021. "Cost–Benefit Analysis of a Mass Vaccination Strategy to Control Brucellosis in Sheep and Goats in Northern Iraq" Vaccines 9, no. 8: 878. https://doi.org/10.3390/vaccines9080878