|Estimating the cost-effectiveness of pneumococcal conjugate vaccination in Brazil
|Vespa G, Constenla DO, Pepe C, Safadi MA, Berezin E, de Moraes JC, de Campos CA, Araujo DV, de Andrade AL
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.
This study examined the cost-effectiveness of universal childhood pneumococcal conjugate vaccination compared with no vaccination. The authors concluded that vaccination reduced the health and economic burden of pneumonia and was likely to be cost-effective. The study was well presented and the methods were conventional, which should ensure the validity of the authors’ conclusions.
Type of economic evaluation
Cost-effectiveness analysis, cost-utility analysis
This study examined the cost-effectiveness of universal childhood pneumococcal conjugate vaccination, compared with no vaccination.
The immunisation programme consisted of a three-dose heptavalent pneumococcal conjugate vaccine administered nationally to infants at two, four, and 12 months old. The comparator was no vaccination.
The analysis was based on a decision-analytic model, with a hypothetical cohort of children aged from newborn to five years. The time horizon was 10 years and the authors stated that the perspectives of both the health care system and society were considered.
The clinical data were from a selection of relevant sources. Most of the epidemiological data, including vaccine coverage, were from country-specific official databases and surveys. The vaccine efficacy was the key model input and was from a published randomised controlled trial (RCT) carried out in the USA by Kaiser Permanente; no Brazilian studies were available. The most appropriate estimates were selected from the available evidence and some assumptions were made.
Monetary benefit and utility valuations:
The disability weights were from published studies.
Measure of benefit:
Disability-adjusted life-years (DALYs) were the summary benefit measure and they were discounted at a rate of 3% per annum. Life-years saved were reported.
The economic analysis included the direct medical costs of vaccine acquisition and administration, laboratory tests, other procedures, medications, supplies, facilities, and personnel, as well as the direct non-medical costs of transport, childcare, home care, time waiting for care, and time undergoing care, and the indirect costs of caregiver productivity lost due to infant illness or death, and government benefits for patients with disabilities. The cost of the vaccine was unknown in Brazil and was based on the price paid by the Pan American Health Organization's Revolving Fund for Vaccine Procurement at the time of the study. The costs of administration and wastage were based on expert opinion. Resource use for the direct costs was from detailed interviews with 16 physicians in Brazil and the unit costs were based on in-patient and out-patient charges. Resource use for other costs was based on authors’ opinions and the costs were from official sources. Indirect costs were based on the average minimum salary in Brazil. The costs were in US dollars ($) and Brazilian reais (BRL). The price year was 2006 and a 3% annual discount rate was applied.
Analysis of uncertainty:
Three alternative scenarios were considered, based on various sources for costs. A four-dose vaccination schedule was considered. A series of one-way sensitivity analyses was performed on selected inputs, using wide ranges of values. The inclusion of herd-protection effects was tested using US data.
In the hypothetical birth cohort of 3,469,937 children, vaccination would save 112,173 DALYs compared with no immunisation. It would avert BRL 59.4 million ($30.6 million) per year in direct medical costs (health care perspective) plus BRL 29.9 million ($15.4 million) per year in non-medical and indirect costs (societal perspective). The total vaccination costs amounted to BRL 527.9 million ($272 million) per year.
The incremental cost per DALY averted was BRL 4,516 ($2,328) from the health care perspective and BRL 3,946 ($2,034) from the societal perspective. At the World Health Organization (WHO) guideline measure for cost-effectiveness (based on the per capita gross domestic product of BRL 12,437), vaccination was found to be very cost-effective.
This cost-effectiveness of vaccination held with lower vaccine prices (base case BRL 51.12), in the scenarios with alternative sources for the costs, and in the sensitivity analyses, but vaccine price and efficacy were influential inputs. The breakeven point for the vaccine dose price was BRL 5.63 (from the societal perspective).
The inclusion of herd immunity produced more favourable ratios, reducing the cost per DALY averted to BRL 1,302 from the societal perspective and BRL 1,490 from the health care perspective.
The authors concluded that pneumococcal vaccination reduced the health and economic burden of pneumonia and was likely to be cost-effective, compared with other options to control childhood diseases.
The selection of the comparators was appropriate as the proposed immunisation was compared against the usual care of no vaccination, in several settings. Two vaccination schedules, with three and four doses, were considered.
A systematic review to identify the relevant sources of evidence was not reported. Country-specific official statistics were used for most of the epidemiological inputs, but little information on the data sources was provided. US data were used for the vaccine, as no Brazilian data were available, and adjustments were made to the Brazilian setting, for factors such as the prevalence of serotypes. The possible heterogeneity of data from various sources does not appear to have been considered. The derivation of the disutility weights was not clearly reported. DALYs were a valid benefit measure for this intervention.
The economic analysis was satisfactorily carried out. Two perspectives were considered and the cost categories, data sources, assumptions, and methods of calculation were clearly presented. The price year and discounting were reported. Some data on resource use were based on expert opinion, but these were explicitly presented. Alternative scenarios considered costs from other sources, and the impact of these data on the cost-effectiveness ratios was investigated.
Analysis and results:
The results were extensively presented and an appropriate approach was used to synthesise the costs and benefits. Alternative scenarios were considered in the sensitivity analysis, including variations in the vaccine price, which was not officially available in the authors’ setting. The impact of variations in other inputs was satisfactorily investigated, but a multi-way sensitivity analysis could have assessed the overall uncertainty in the findings. The authors acknowledged some limitations of their analysis and these mainly related to the lack of Brazilian data for some parameters. The analysis was generally conservative against the vaccination programme.
The study was well presented and the methods were conventional, which should ensure the validity of the authors’ conclusions.
Funded by Wyeth Industria Farmaceutica, Sao Paulo, Brazil.
Vespa G, Constenla DO, Pepe C, Safadi MA, Berezin E, de Moraes JC, de Campos CA, Araujo DV, de Andrade AL. Estimating the cost-effectiveness of pneumococcal conjugate vaccination in Brazil. Pan American Journal of Public Health 2009; 26(6): 518-528
Subject indexing assigned by NLM
Brazil; Cost-Benefit Analysis; Humans; Incidence; Pneumococcal Infections /epidemiology /prevention & Pneumococcal Vaccines /economics; Spouse Abuse; Vaccines, Conjugate; control
Date bibliographic record published
Date abstract record published