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Cost-effectiveness of childhood hepatitis A vaccination in Argentina: a second dose is warranted |
Ellis A, Ruttimann R W, Jacobs R J, Meyerhoff A S, Innis B L |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. CRD summary The aim of the study was to perform an economic evaluation of childhood vaccination against hepatitis A, compared with no vaccination, in five geographic regions of Argentina. The evaluation focused on the need for a second dose of vaccine added to the current one-dose schedule. The authors concluded that the one-dose schedule was cost-saving compared with no vaccination, while the second-dose schedule, especially at age 18 months, was cost-effective. Overall, the study was carried out in a robust fashion with good presentation of the results. In general, the authors’ conclusions appear robust, although the provision of more details on some clinical estimates would have been helpful. Type of economic evaluation Study objective The aim of the study was to undertake an economic evaluation of childhood vaccination against hepatitis A, compared with no vaccination, in five geographic regions of Argentina. Specifically, the analysis focused on the need for a second dose of vaccine added to the current one-dose schedule. Interventions Four immunisation programmes were compared:
no vaccination;
one-dose vaccination at 12 months of age;
two-dose vaccinations at 12 and 72 months of age; and
two-dose vaccinations at 12 and 18 months of age. Methods Analytical approach:A published Markov model was used to determine the long-term costs and benefits of the different immunisation programmes on the basis of several published sources. The time horizon of the analysis was 50 years. A societal perspective was adopted.
Effectiveness data:Most epidemiological estimates were derived from data published by the Ministry of Health of Argentina (surveillance databases) and a review of records from a local hospital. National and regional data were used to estimate variability in Argentinean regions. Vaccine efficacy was taken from other published studies, details of which were not given but which appear to have been identified selectively. Vaccine coverage was assumed to be similar to that of other vaccine programmes in Argentina. The risk of hepatitis A due to personal contacts was taken from a US study. The key clinical input of the model was vaccine effectiveness.
Monetary benefit and utility valuations:Utility estimates were based on data derived from a published study, no details of which were given.
Measure of benefit:The summary benefit measure was the quality-adjusted life-years (QALYs). These were estimated using the decision model. Future QALYs were discounted at an annual rate of 3%. The numbers of cases and deaths prevented were also reported.
Cost data:The categories of costs included in the analysis were vaccine (acquisition and administration), outpatient services, hospital stay for acute liver disease or liver transplant, and work loss for adult patients. All these costs were calculated on the basis of hepatitis A cases, both in the birth cohort and in personal contacts. Work loss for parents of children with disease symptoms was not considered. Vaccine cost was based on a median price quotation. The medical costs of hepatitis A were derived from a review of records from a local hospital. The cost of work loss was based on region-specific wage rates. The sources of the resource use data were not clear. The costs were in US dollars ($) and the price year was 2005. The costs were discounted because of the long-term horizon of the analysis, and an annual discount rate of 3% was applied.
Analysis of uncertainty:In a two-way deterministic sensitivity analysis, vaccine price and duration of vaccine protection were varied simultaneously. Results The one-dose vaccination policy reduced each birth cohort member’s 50-year probability of overt hepatitis A from 7.2% to 4.1%. A second dose reduced this probability to between 2.0% and 2.2%.
Over a 50-year time horizon, the QALYs lost due to hepatitis A in the birth cohort of 2005 were 5,705 with no vaccination, 2,481 with vaccination at 12 months, 1,360 with vaccination at 12+72 months, and 1,137 with vaccination at 12+18 months. The corresponding lost QALYs for personal contacts were 13,715 (no vaccination), 2,402 (vaccination at 12 months), 1,849 (vaccination at 12+72 months) and 1,150 (vaccination at 12+18 months).
The total costs in the whole birth cohort and in personal contacts were $27.216 million with no vaccination, $11.958 million with vaccination at 12 months, $13.547 million with vaccination at 12+72 months, and $13.388 million with vaccination at 12+18 months.
In the whole country, vaccination at 12 months was dominant over no vaccination (more effective and less costly), while the incremental cost per QALY gained was $949 with vaccination at 12+72 months and $551 with vaccination at 12+18 months.
Regional-level data reflecting different epidemiological settings were also reported. In general, a second dose at age 18 months was more cost-effective than a second dose at age 72 months.
The sensitivity analysis did not substantially alter the base-case findings. Authors' conclusions The authors concluded that the first dose of hepatitis A vaccination led to greater benefits than the second dose in the Argentine health care system. However, a second dose of vaccine, especially if administered at age 18 months, would still be cost-effective from an economic standpoint. CRD commentary Interventions:The choice of the immunisation programmes was appropriate as they were the most relevant alternatives, not only in the authors’ setting but also in other countries.
Effectiveness/benefits:The sources used to derive the clinical estimates were identified selectively. The selection of national and regional databases was appropriate given that they reflected the specific epidemiological context considered in the study. No justification for the selection of other sources of data was provided. Furthermore, the authors did not describe the design and other characteristics of published studies, which would have been particularly important for vaccine effectiveness. This limits the possibility of objectively assessing the validity of the clinical estimates. There was little information on the approach used to derive the benefit measure since the utility weights were derived from a previous study.
Costs:The analysis adopted a broad viewpoint, which included all relevant categories of costs. The sources of the costs, price year, use of discounting and currency were reported. However, few details of the evaluation of resource consumption were given and the unit costs and resource quantities were not presented separately, except for vaccine costs. The authors noted that some non-medical costs were not included as they could not be valued.
Analysis and results:The synthesis of the costs and benefits was appropriately carried out. The issue of uncertainty was addressed only using a deterministic analysis on key parameters of the model. A wider approach (i.e. more parameters under examination) would have been more appropriate. The analysis focused on the Argentine setting and caution will be needed if extrapolating the results of the analysis to other contexts. In general, the authors stated that conservative assumptions were made, and this represents a strength of the analysis. Another strong characteristic of the analysis was the detailed presentation of data and results at a regional level.
Concluding remarks:The analysis appears to have been carried out satisfactorily in terms of methodology and reporting although, on occasions, the information on some sources of data was described in insufficient detail. The authors’ conclusions appear valid and appropriate. Funding Supported by a grant from Glaxo SmithKline. Bibliographic details Ellis A, Ruttimann R W, Jacobs R J, Meyerhoff A S, Innis B L. Cost-effectiveness of childhood hepatitis A vaccination in Argentina: a second dose is warranted. Pan American Journal of Public Health 2007; 21(6): 345-356 Other publications of related interest Jacobs RJ, Greenberg DP, Koff RS, et al. Regional variation in the cost effectiveness of childhood hepatitis A immunization. Pediatr Infect Dis J 2003;22:904–14.
Valenzuela MT, Jacobs RJ, Arteaga O. Cost-effectiveness of universal childhood hepatitis A vaccination in Chile. Vaccine 2005;23:4110–9.
Ginsberg GM, Slater PE, Shouval D. Cost-benefit analysis of a nationwide infant immunization programme against hepatitis A in an area of intermediate endemicity. J Hepatol 2001;34:92–9.
Jacobs RJ, Moleski, RJ, Meyerhoff AS. The value of hepatitis A prevention based on time trade-off and willingness-to-pay measurement. Pharmacoeconomics 2002;20:739–47. Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Age Factors; Argentina /epidemiology; Child; Child, Preschool; Cohort Studies; Cost-Benefit Analysis; Hepatitis A /economics /epidemiology /prevention & Hepatitis A Vaccines /administration & Humans; Immunization Schedule; Immunization, Secondary; Incidence; Infant; Markov Chains; Middle Aged; Quality-Adjusted Life Years; Vaccination /economics; control; dosage /economics AccessionNumber 22007006630 Date abstract record published 09/08/2008 |
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