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Public health and economic impact of vaccination with 7-valent pneumococcal vaccine (PCV7) in the context of the annual influenza epidemic and a severe influenza pandemic |
Rubin JL, McGarry LJ, Klugman KP, Strutton DR, Gilmore KE, Weinstein MC |
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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 This study assessed the cost-effectiveness of routine infant vaccination with the heptavalent pneumococcal conjugate vaccine (PCV7), in the context of an annual influenza epidemic or a severe influenza pandemic. The authors concluded that vaccination was highly effective and cost-saving from the payer’s perspective, in either context. The methods were valid and the authors’ conclusions are robust, but more details of the data sources would have allowed a more thorough assessment of their validity. Type of economic evaluation Cost-effectiveness analysis, cost-utility analysis Study objective This study assessed the cost-effectiveness of routine infant vaccination with the heptavalent pneumococcal conjugate vaccine (PCV7) in the general population, in the context of an annual influenza epidemic or a severe influenza pandemic. Interventions Routine vaccination, using PCV7, for infants at two, four, six, and 12 to 15 months of age was compared with no vaccination. Methods Analytical approach:The economic evaluation was based on a decision-analytic model that considered the effects of one influenza season, over a lifetime horizon. The authors stated that their study was carried out from the perspective of the payer.
Effectiveness data:The efficacy and epidemiology data were from a selection of relevant studies. The key inputs were those relating to the direct and indirect or herd effects of vaccination. These were derived from a published clinical trial; the Northern California Kaiser Permanente (NCKP) trial. Other epidemiological inputs were mainly from national databases and registries. Several assumptions and adjustments were needed and these were conservative against the vaccination strategy.
Monetary benefit and utility valuations:The utility estimates were from a published cost-effectiveness analysis of pneumococcal vaccination.
Measure of benefit:Life-years (LYs) and quality-adjusted life-years (QALYs) were the summary benefit measures. A 3% annual discount rate was applied. The numbers of invasive pneumococcal disease cases, pneumonia cases, invasive pneumococcal disease deaths, and pneumonia deaths were also reported.
Cost data:The economic analysis included the direct medical costs associated with vaccination and the treatment of the following conditions: meningitis (deafness and disability), bacteraemia, pneumonia, and otitis media. The cost of vaccination was from official data from the Centers for Disease Control and Prevention (CDC). Other costs and resource consumption were from US published sources. The costs were in US dollars ($) and were discounted at an annual rate of 3%. The price year was 2006.
Analysis of uncertainty:A deterministic approach was used to examine how robust the base-case findings were to variations in selected model inputs, such as the efficacy of vaccination, the indirect effects of vaccination, the proportion of patients treated, the bacteraemic pneumonia incidence, and the case-fatality rate. The alternative assumptions were made by the authors or were published ranges of values. Results In the epidemic influenza scenario, with an incidence of 13%, considering the whole US population of 300 million, the routine infant PCV7 vaccination prevented 32,300 invasive pneumococcal disease cases, 550,100 pneumonia cases, 2,200 invasive pneumococcal disease deaths, and 21,000 pneumonia deaths, saving $1.57 billion. Vaccination was the dominant strategy as it was more effective and less expensive than no vaccination.
In the pandemic influenza scenario, with an incidence of 30%, vaccination led to 2.0 million LYs saved, 2.1 million QALYs gained, and $7.34 billion saved. The indirect protection (herd immunity) for the unvaccinated population prevented 84% of deaths.
These results were robust, in the sensitivity analysis. The most influential inputs were the reductions in the incidence and case-fatality rates of bacteraemic pneumonia and all-cause pneumonia. Even in a scenario with low (0%) herd immunity effects from vaccination on pneumonia, the immunisation strategy remained dominant. Authors' conclusions The authors concluded that vaccination was highly effective and cost-saving from the payer’s perspective in both the contexts studied. CRD commentary Interventions:The two strategies were appropriately selected; the proposed vaccination strategy was compared against no vaccination.
Effectiveness/benefits:Limited information on the derivation of the clinical inputs was provided. The data sources appear to have been selected without a literature review, as the methods and conduct of such a review were not reported. In general, valid sources of evidence appear to have been used. For example, a national database was a valid source of administrative data that were representative of the patient population. Similarly, inputs from trials are generally used for vaccine efficacy, but the details of these sources would have helped in objectively assessing the validity of these inputs. Some assumptions were made, but these were generally conservative against the vaccination strategy. All the benefit measures were valid and relevant for different stakeholders. In particular, LYs and QALYs allow cross-disease comparisons to be made.
Costs:The economic analysis was only partly reported. The authors provided little information on the cost categories, unit costs, and resource quantities. The data were generally from published US studies, but the details of these sources would have been useful. These data appear to have been specific to the USA and might not be transferable to other settings. The cost estimates do not appear to have been included in the sensitivity analysis and variations in these inputs were not assessed.
Analysis and results:The costs and benefits were analysed, using an incremental approach, which was appropriate for demonstrating the dominance of vaccination over no intervention. Only the incremental results were reported, and the total costs and benefits of the two strategies were not given. The sensitivity analyses focused on the most uncertain inputs. A more comprehensive approach, based on the simultaneous variation of several inputs, would have helped in assessing alternative scenarios. The key assumptions of the two main scenarios (epidemic and pandemic) were reported and they were extensively varied in the sensitivity analysis.
Concluding remarks:The methods were valid and the authors’ conclusions are robust, but more details of the data sources would have allowed a more thorough assessment of their validity. Funding Funded by Wyeth Research (now Pfizer). Bibliographic details Rubin JL, McGarry LJ, Klugman KP, Strutton DR, Gilmore KE, Weinstein MC. Public health and economic impact of vaccination with 7-valent pneumococcal vaccine (PCV7) in the context of the annual influenza epidemic and a severe influenza pandemic. BMC Infectious Diseases 2010; 10:14 Indexing Status Subject indexing assigned by NLM MeSH Adolescent; Adult; Aged; Child; Child, Preschool; Costs and Cost Analysis; Heptavalent Pneumococcal Conjugate Vaccine; Humans; Immunity, Herd; Incidence; Infant; Influenza A Virus, H1N1 Subtype; Influenza, Human /economics /epidemiology; Middle Aged; Models, Economic; Pneumococcal Infections /economics /epidemiology /prevention & Pneumococcal Vaccines /administration & Public Health /economics; Young Adult; control; dosage /economics AccessionNumber 22010000654 Date bibliographic record published 29/09/2010 Date abstract record published 24/11/2010 |
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