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The economics of hepatitis B virus vaccination: an analysis of cost-effectiveness results for Switzerland |
Zurn P, Carrin G, Danthine J P, Kammerlander R, Kane M |
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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. Health technology Hepatitis B virus vaccination.
Economic study type Cost-effectiveness analysis.
Study population The study population was a birth cohort of 85,000 Swiss individuals.
Setting Hospital. The study was set in Switzerland.
Dates to which data relate Effectiveness and resource use data were collected from studies published between 1983 and 1996. Cost data were collected from 1996 sources. The price year was 1996.
Source of effectiveness data Effectiveness data were derived from a literature review and expert opinion.
Modelling A lifetime decision analytic model was used to determine the cost-effectiveness of the vaccination strategies.
Outcomes assessed in the review The review assessed the following outcomes: compliance with screening and vaccination, hepatitis B prevalence, probability of HBV infection, long-term complications (LTC), and clinical outcomes of LTCs.
Study designs and other criteria for inclusion in the review Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Summary statistics from individual studies were used.
Number of primary studies included At least 9 studies were included.
Methods of combining primary studies Investigation of differences between primary studies Results of the review For newborns and infants, the prevalence of HB surface antigen positive was 0.5%, and the prevalence of HB antigen positive was 10%. Protective levels of anti-HBs were 95% for newborns and infants, and 88.5% for school children and adolescents. The probability of long-term complications was 25% for perinatal infection and 20% for subsequent infection. The probability of clinical outcomes of long-term complications that were not treated was 25% for chronic persistent hepatitis, 12.5% for chronic active hepatitis, 25% for cirrhosis, and 37.5% for HCC. The probability of hospitalisation was 100% for perinatal infection and 28% for subsequent infection. The probability of death with fulminant hepatitis was 70%.
Methods used to derive estimates of effectiveness Expert opinion. Effectiveness estimates were derived from a clinical panel consisting of 7 experts.
Estimates of effectiveness and key assumptions For newborns and infants, compliance with screening was estimated to be 80%. For newborns, compliance with vaccination was 95% and for infants, 90%. For school children and adolescents, compliance with vaccination was 85%. For newborns and infants the lifetime probability of HBV infection was 5%. For school children and adolescents the lifetime probability of HBV infection was 5%. The probability of patients who were not treated or who did not respond was 88%. The probability of clinical outcomes of long-term complications treated with success was 0% for chronic persistent hepatitis, chronic active hepatitis, and cirrhosis, and 12% for hepatocellular carcinoma, and 88% for recovery.
Measure of benefits used in the economic analysis The numbers of lives saved and the number of life years saved were used as the measures of benefit. Benefits were discounted at an annual rate of 3%.
Direct costs Direct costs were discounted at an annual rate of 3%. Quantities and costs were reported separately. Direct costs included the HBV prevention costs (cost of screening, drug costs, costs of delivery of HB immunoglobulin) and treatment costs resulting from HBV infection (i.e. lifetime health care costs of HBV complications). The quantity/cost boundary adopted was that of society. The estimation of quantities and costs was based on actual data. Drug costs were based on wholesale prices. Costs were collected from the Lausanne Hospital, a regional hospital, and the VESKA database. The price year was 1996.
Statistical analysis of costs No statistical analysis of costs was reported.
Indirect Costs Indirect costs were discounted at an annual rate of 3%. Quantities and costs were reported separately. Indirect costs of morbidity and mortality were estimated using the human capital approach. The gross domestic product per capita was used as the measure of the indirect costs of a full year of labour lost. The quantity/cost boundary adopted was that of society. The estimation of quantities and costs was based on actual data. The price year was 1996.
Currency Swiss Francs (SFr), (US$1 = SFr1.235).
Sensitivity analysis Extensive one-way sensitivity analyses were conducted on all model parameters over plausible ranges.
Estimated benefits used in the economic analysis With systematic prenatal screening and vaccination of newborns at risk, vaccination compliance was 95%. 1,436 acute infections would still occur, there would be 355 chronic infections and 56 deaths.
With universal vaccination of infants, vaccination compliance was 90%, 288 acute infections, 83 chronic infections and 13 deaths.
With universal vaccination of school children, vaccination compliance was 85%, 360 acute infections, 101 chronic infections and 16 deaths.
With universal vaccination of infants and school children, vaccination compliance was 90% for infants and 85% for school children. There would be 668 acute infections, 220 chronic infections and 35 deaths.
With universal vaccination of infants, school children, and adolescents, vaccination compliance was 90% for infants, 85% for school children, and 80% for adolescents. There would be 1,112 acute infections, 371 chronic infections and 60 deaths.
137 years of life would be saved with systematic prenatal screening and vaccination of newborns at risk, 871 with universal vaccination of infants, 823 with universal vaccination of school children, 1,557 with universal vaccination of infants and school children, and 2,202 with universal vaccination of infants, school children, and adolescents.
Cost results Total costs amounted to:
SFr3,184,440 with systematic prenatal screening and vaccination of newborns at risk;
SFr7,673,430 with universal vaccination of infants;
SFr10,184,390 with universal vaccination of school children;
SFr14,869,250 with universal vaccination of infants and school children;
SFr21,628,720 with universal vaccination of infants, school children, and adolescents.
Synthesis of costs and benefits The incremental cost per life year saved was:
SFr159,300 with systematic prenatal screening and vaccination of newborns at risk;
SFr59,290 with universal vaccination of infants;
SFr53,970 with universal vaccination of school children;
SFr52,400 with universal vaccination of infants and school children.
The incremental cost per life year saved with universal vaccination of infants, school children, and adolescents over systematic prenatal screening and vaccination of newborns at risk was SFr60,960. These results were sensitive to changes in prevalence, vaccine price, and discount rate.
Authors' conclusions Incremental cost-effectiveness ratios are lower with universal vaccination strategies than with selective vaccination. With universal vaccination strategies increasingly ambitious strategies result in higher costs, but also in more incremental years of life saved.
CRD COMMENTARY - Selection of comparators A justification was given for the comparator used, namely that it represented current practice. You, as a user of the database, should decide if these health technologies are relevant to your setting.
Validity of estimate of measure of benefit Although a range of sources was used, the authors did not describe a systematic review of the literature. More details could have been provided about the design of the review and the method of combining primary effectiveness estimates. The estimation of benefits was obtained directly from the effectiveness analysis. The authors acknowledged that their approach was static by not allowing for differences in prevalence on a yearly basis. Extensive sensitivity analyses were performed to take into account variability in the data.
Validity of estimate of costs Good features of the study were that all relevant cost categories were included for the perspective adopted, quantities and costs were reported separately, sensitivity analyses were conducted on costs and on quantities, and the price year was reported. Cost estimates were based on diagnostic costs and some charges.
Other issues The authors did not make appropriate comparisons of their findings with those from other studies and the issue of generalisability to other settings was not addressed. The authors did not present their results selectively. The authors examined subjects potentially at risk from HBV and this was reflected in their conclusions.
Implications of the study The authors recommended that the universal vaccination of school children should be the adopted policy
Bibliographic details Zurn P, Carrin G, Danthine J P, Kammerlander R, Kane M. The economics of hepatitis B virus vaccination: an analysis of cost-effectiveness results for Switzerland. Disease Management and Health Outcomes 2000; 7(6): 331-347 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Child; Child, Preschool; Cost-Benefit Analysis; English Abstract; Female; Hepatitis B /economics /prevention & Hepatitis B Vaccines /economics /administration & Humans; Immunization Programs /economics; Immunization Schedule; Infant; Infant, Newborn; Male; Pregnancy; Switzerland; control; dosage AccessionNumber 22000001115 Date bibliographic record published 31/03/2001 Date abstract record published 31/03/2001 |
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