Are economic evaluations of vaccines useful to decision-makers? Case study of Haemophilus influenzae type b vaccines

Benefit-Risk Assessment of Vaccines. Part I: A Systematic Review to Identify and Describe Studies About Quantitative Benefit-Risk Models Applied to Vaccines

Introduction

Understanding the balance between the benefits and risks of vaccination is essential to ensure informed and adequate public health decision making. Quantitative benefit–risk models (qBRm) represent useful tools to help decision makers with supporting benefit–risk assessment throughout the lifecycle of a medical product. However, few initiatives have been launched to harmonise qBRm approaches, specifically for vaccines.

Objectives

The aim of this paper was to identify publications about qBRm applied to vaccines through a systematic literature review, and to describe their characteristics.

Methods

Medline, Scopus and Institute for Scientific Information Web of Knowledge databases were searched to identify articles in English, published from database inceptions up to December 2019. The search strategy included the combination of three key concepts: ‘benefit–risk’, ‘modelling’ and ‘vaccines’. Data extracted included the modelling context and the methodological approaches used.

Results

Of 3172 publications screened, 48 original publications were included. Most of the selected studies were published over the past decade and focused on rotavirus (15), dengue (10) and influenza (6) vaccines. The majority (30) of studies reported analyses related to high-income countries. The methodology of the studies differed, particularly in modelling techniques, benefit–risk measures, and sensitivity analyses. The present work also pointed out a high level of variability in the quality of reporting across studies, with particular regard to input parameters and methodological approaches.

Conclusions

This review provides an extensive list of qBRm applied to vaccines. Discrepancies across studies were identified during our review. While the number of published qBRm studies is increasing, no reporting guidance for qBRm applied to vaccines is currently available. This may affect decision makers’ confidence in the results and their benefit–risk assessment(s); therefore, the development of such reporting guidance is highly needed.

Electronic supplementary material

The online version of this article (10.1007/s40264-020-00984-7) contains supplementary material, which is available to authorized users.

Benefit-Risk Assessment of Vaccines. Part II: Proposal Towards Consolidated Standards of Reporting Quantitative Benefit-Risk Models Applied to Vaccines (BRIVAC)

INTRODUCTION

Quantitative benefit-risk models (qBRm) applied to vaccines are increasingly used by public health authorities and pharmaceutical companies as an important tool to help decision makers with supporting benefit-risk assessment (BRA). However, many publications on vaccine qBRm provide insufficient details on the methodological approaches used. Incomplete and/or inadequate qBRm reporting may affect result interpretation and confidence in BRA, highlighting a need for the development of standard reporting guidance.

OBJECTIVES

Our objective was to provide an operational checklist for improved reporting of vaccine qBRm.

METHODS

The consolidated standards of reporting quantitative Benefit-RIsk models applied to VACcines (BRIVAC) were designed as a checklist of key information to report in qBRm scientific publications regarding the assessed vaccines, the methodological considerations and the results and their interpretation.

RESULTS

In total, 22 items and accompanying definitions, recommendations, explanations and examples were provided and divided into six main sections corresponding to the classic subdivisions of a scientific publication: title and abstract (items 1-2), introduction (items 3-4), methods (items 5-15), results (items 16-17), discussion (items 18-20) and other (items 21-22).

CONCLUSIONS

The BRIVAC checklist is the first initiative providing an operational checklist for improved reporting of qBRm applied to vaccines in scientific articles. It is intended to assist authors, peer-reviewers, editors and readers in their critical appraisal. Future initiatives are needed to provide methodological guidance to perform qBRm while taking into account the vaccine specificities.

Economic evaluations of Haemophilus influenzae type b (Hib) vaccine: a systematic review

AIMS

The World Health Organization (WHO) recommends the use of Haemophilus influenzae type b (Hib) conjugate vaccines, but China and Thailand have not used Hib vaccination in their national immunization programs. This systematic review aimed to update published economic evaluations of Hib vaccinations and to determine factors that potentially affected their cost-effectiveness.

METHODS

Searches were performed from the inception until December 2015 using 13 databases: CAB direct; CEA registry; EconLit; EMBASE; E-library; NHSEED; PAHO; POPLINE; PubMed; Redalyc project; RePEc; SciELO; and WHOLIS. Reference lists of relevant studies and grey literature were also searched. Full economic evaluations of Hib vaccination with results of costs and outcomes were included. The WHO checklist was used to evaluate the quality of the included studies. Data from eligible studies were extracted using a standardized data collection form.

RESULTS

Out of 830 articles, 27 were included. Almost half of the studies (12/27) were conducted in high-income countries. Twelve studies (12/27) investigated the Hib vaccine as an addition to the existing vaccination program. Most studies (17/27) examined a 3-dose schedule of Hib vaccine. Nineteen studies (19/27) reported the model used, where all were decision tree models. Most of the studies (23/27) demonstrated an economic value of Hib vaccination programs, key influential parameters being incidence rates of Hib disease and vaccine price.

CONCLUSIONS

Hib vaccination programs are mostly found to be cost-effective across geographic regions and country income levels, and Hib vaccination is recommended for inclusion into all national immunization programs. The findings are expected to support policy-makers for making decisions on allocating limited resources of the Hib vaccination program effectively.

Foresight in medicine: current challenges with Haemophilus influenzae type b conjugate vaccines

An effective vaccine to prevent invasive infections caused by Haemophilus influenzae type b (Hib) bacteria has been available for more than 20 years. Hib conjugate vaccine is safe, efficacious and easy to use, and its cost-benefit ratio is high both in industrialized as well as in developing countries. In spite of this, WHO estimates that every year approximately 8 million children contract life-threatening Haemophilus infections, especially meningitis or severe pneumonia. If we want to take seriously the Millenium Development Goal of reducing the mortality of under 5-year-old children by two-thirds before the year 2015, an effective means to contribute to this would be more efficient use of Hib vaccines.

A brief history of economic evaluation for human papillomavirus vaccination policy

Background: This commentary discusses key issues for health economic evaluation and modelling, applied to human papillomavirus (HPV) vaccine programs. Methods: We outline some of the specific features of HPV disease and vaccination, and associated policy questions in light of a literature search for economic evaluations on HPV vaccination. Results: We observe that some policy questions could not be reliably addressed by many of the 43 published economic evaluations we found. Despite this, policy making on universal HPV vaccination followed shortly after vaccine licensure in many developed countries, so the role economic evaluation played in informing these decisions (pre-dating 2008) seems to have been fairly limited. For more recent decisions, however, economic evaluation is likely to have been used more widely and more intensively. Conclusions: We expect future cost-effectiveness analyses to be more instrumental in policy making regarding vaccines covering more HPV types, therapeutic HPV vaccines, and novel diagnostic tests for biomarkers of HPV infection and disease integrated with cervical screening programs.

WHO Guide for standardisation of economic evaluations of immunization programmes

Traditional EPI vaccines are considered to be among the most efficient uses of scarce health care resources. Today, there are many under-used and new vaccines available. In the short- to medium-term, these vaccines will not cost the few cents per dose the traditional vaccines do, but will be 'multi-dollar' vaccines. Decision-makers will need information, among other things, on their relative cost-effectiveness. A number of reviews have indicated that there is scope for improving the transparency, completeness and comparability of economic evaluations of vaccination programmes. Thus, there is a need to improve the quality of economic evaluations of vaccination programmes. Adherence to general guidelines would increase the quality, interpretability and transferability of future analyses. However, there is reason to believe that there might also be a need for more specific advice for vaccination programmes. For example, there are inconsistencies in the methods used to estimate the future benefits of vaccination programmes and the relative efficiency of these programmes can be sensitive to some of the more controversial aspects of general guidelines, such as the inclusion of indirect costs and the discounting of health outcomes. This guide has been developed in order to meet the needs of decision-makers for relevant, reliable and consistent economic information. They aim to provide clear and concise, practical and high quality guidance for those who conduct economic evaluations.

Economic analysis of childhood pneumonia in Northern Pakistan

OBJECTIVES

This study estimates household costs for treatment of pneumonia, severe pneumonia and very severe febrile disease. Combined with reported costs from the health care provider perspective, an estimate of the overall financial burden of these diseases has been developed for the Northern Areas of Pakistan.

METHODS

Data on the duration and economic implications of the illnesses for households were collected from caretakers of children under 3 years of age enrolled in a surveillance study who sought care at a health facility. Trained study physicians and health workers identified children with pneumonia, severe pneumonia and very severe febrile disease--as defined by protocols for the Integrated Management of Childhood Illness (IMCI).

RESULTS

From January to December 2002, 141 health facility visits for pneumonia (n = 41, 29%), severe pneumonia (n = 65, 46%) and very severe febrile disease (n = 35, 25%) were recorded for 112 children who sought care at various levels of health facilities in the Northern Areas of Pakistan. The total societal average cost per episode was US$22.62 for pneumonia, US$142.90 for severe pneumonia and US$62.48 for very severe febrile disease. For household expenditures, medicines constituted the highest proportion (40.54%) of costs incurred during a visit to the health facility, followed by meals (23.68%), hospitalization (13.23%) and transportation (12.19%).

CONCLUSION

Pneumonia is one of the leading killers of children in Pakistan with a correspondingly high economic burden to society. The results of this study suggest that there is a strong economic justification for expanding the availability of existing interventions to fight pneumonia, and for introducing measures such as vaccines to prevent pneumonia episodes.

Cost-benefit analysis of haemophilus influenzae type B immunization in Korea

An economic evaluation of Haemophilus influenzae type b (Hib) immunization was conducted to examine whether Hib immunization should be included in Korea's national immunization program. The costs and benefits included direct and indirect values and an estimation of the economic efficiency. We determined that a universal Hib immunization program in Korea would prevent 17 deaths and 280 invasive Hib cases. When we assumed the one Hib immunization cost as 26,000 won, the national Hib immunization would cost 34.6 billion won. Costs for various Hib diseases were estimated at 26.8 billion won (11.8 billion won from direct costs and 14.9 billion won from indirect costs). A benefit-cost ratio of 0.77 showed that the economic efficiency of the integration of Hib immunization in Korea is low because of the low incidence rate of Hib disease and high price of vaccine. However, if the Hib immunization cost decrease to less than 20,000 won, a benefit-cost ratio increase to 1.0 and above, integrating Hib immunization into the national immunization program with economic efficiency can be considered.

Cost-effectiveness analyses of vaccination programmes : a focused review of modelling approaches

Cost effectiveness is becoming an increasingly important factor for stakeholders faced with decisions about adding a new vaccine into national immunization programmes versus alternative use of resources. Evaluating cost effectiveness, taking into account the relevant biological, clinical, epidemiological and economic factors of a vaccination programme, generally requires use of a model. This review examines the modelling approaches used in cost-effectiveness analyses (CEAs) of vaccination programmes.After overviewing the key attributes of models used in CEAs, a framework for categorising theoretical models is presented. Categories are based on three main attributes: static/dynamic; stochastic/deterministic; and aggregate/individual based. This framework was applied to a systematic review of CEAs of all currently available vaccines for the period of 1976 to May 2007. The systematic review identified 276 CEAs of vaccination programmes. The great majority (83%) of CEAs were conducted in the setting of high-income countries. Only a few vaccines were widely studied, with 57% of available CEAs being focused on the varicella, influenza, hepatitis A, hepatitis B or pneumococcal vaccine. Several time trends were evident, indicating that the number of vaccine CEAs being published is increasing; the main health outcome measures are moving away from the number of cases prevented towards quality-adjusted and unadjusted life-years gained, and more complex models are beginning to be used. The modelling approach was often not adequately described. Of the 208 CEAs that could be categorized according to the framework, around 90% were deterministic, aggregate-level static models. Although a dynamic transmission model is required to account for herd-immunity effects, only 23 of the CEAs were dynamic. None of the CEAs were individual based. To improve communication about the cost effectiveness of vaccination programmes, we believe the first step is for analysts to be more transparent with each other. A clear description of the model type using consistent terminology and justification for the model choice must begin to accompany all CEAs. As a minimum, we urge modellers to provide an explicit statement about the following attributes: static/dynamic; stochastic/deterministic; aggregate/individual based; open/closed. Where relevant, time intervals (discrete/continuous) and (non)linearity should also be described. Enhanced methods of assessing model performance and validity are also required. Our results emphasize the need to improve modelling methods for CEAs of vaccination programmes; specifically, model choice, construction, assessment and validation.

Introduction of Hib vaccine into national immunization programmes: A descriptive analysis of global trends

Despite the demonstration of effectiveness and public health impact of Hib conjugate vaccines, the majority of infants from poorest countries do not yet have access to this safe and effective preventive intervention. This paper provides a descriptive analysis of the main characteristics of countries that have included Hib vaccine in their national immunization programmes before 2006. It highlights the importance of regularly analyzing the process of decision-making involved in implementation of public health interventions, in order to learn from cumulative experience and expedite the introduction of future interventions.

Sense and the science of childhood immunization: Can we achieve more with less?

The threat of biological terrorism with small pox virus and a global influenza pandemic in the face of limited vaccine supply recently stimulated research into the evaluation of fractional dose vaccine regimens, with promising immunogenicity results. While this approach is not new, it has been less applied to vaccines for less sensational but nevertheless, significant killer diseases. This manuscript provides an overview of the basics of immunization as it applies to the current practice of immunization in children, comments on the untapped avenues for cost reduction of vaccine delivery, and the potential for saving more lives with currently available resources.

Economic evaluation of Haemophilus influenzae type b vaccination in Moscow, Russian Federation

OBJECTIVE

To estimate the cost-effectiveness of providing Haemophilus influenzae type b (Hib) vaccine to children in Moscow in routine immunization services.

METHODS

The incidence of Hib meningitis among children aged <5 years in Moscow was obtained from a prospective surveillance study undertaken during October 1999-September 2001, with treatment cost data collected for all cases. Sequelae in surviving children were assessed in December 2002. The costs of Hib vaccination in Moscow were estimated assuming a vaccine price of US dollar 5 per dose and the same four-dose schedule and 97% coverage as for diphtheria-tetanus-pertussis vaccine. The most uncertain variables were varied in a sensitivity analysis.

RESULTS

The annual incidence of Hib meningitis was 5.7 per 100,000 children <5 years. The average treatment cost for an acute Hib meningitis case was US dollar 1296. For a patient with sequelae, the average additional lifetime discounted treatment cost was US dollar 15,820. The total annual cost of Hib vaccination of infants in Moscow was estimated as US dollar 1.5 million per year. In the base case analysis, the cost-effectiveness ratios amount to US dollar 77,503 per Hib meningitis case averted and US dollar 10,842 per discounted disability adjusted life year averted. The break-even vaccine price, where the annual vaccination costs equal annual treatment costs averted, is only US dollar 0.04 per dose in the base case scenario. If discounted indirect costs are included, the break-even vaccine price is US dollar 0.5 per dose.

CONCLUSION

In Moscow, the incidence of Hib meningitis is low and the costs of hospitalization and subsequent medical treatment are relatively inexpensive. Given these factors, Hib vaccine at US dollar 5 per dose would not be a cost-effective option in Moscow at the present time.

Cost-effectiveness of universal pneumococcal vaccination for infants in Italy

This study aimed at estimating the health and economic outcomes of universal infant vaccination with seven-valent pneumococcal conjugate vaccine (PCV-7) in Italy. A Markov model simulated lifetime evolution of a birth cohort (538,138 children): universal vaccination would avert 769 invasive infections, 18 deaths and 1323 life years. At base-case analysis, universal three-dose vaccination would cost euro 26,449 (95% CI: 1975-62,075) and euro 38,286 (95% CI: 22,164-70,801) per life year-saved in the societal and the NHS perspective, respectively. In the hypothesis of a 5-year long protection period, vaccination would cost euro 32,694 and euro 43,115 per life-year saved. Considering yearly incidence of invasive pneumococcal disease reported for Veneto and Sardinia regions, PCV-7 vaccination would result highly cost-effective determining a cost of euro 10,479 and euro 16,890 per life year-save in the NHS and the societal perspective, respectively.

Potential conflicts of interest in vaccine economics research: a commentary with a case study of pneumococcal conjugate vaccination

The main potential areas of bias in economic evaluation (EE) in health care can be categorised as follows: (1) choosing the study question and design, (2) estimating clinical effectiveness; (3) choosing cost data sources, and (4) reporting and dissemination of results. Each of these is discussed while focusing on vaccines. In addition a case study is presented on two contemporary economic evaluations of pneumococcal conjugate vaccination for Canada. Though they are quite similar in design and methods, their results are not quite so. This paper explores the differences between them in relation to the four areas of bias. Finally, remedies to avoid bias in research and publications are proposed and discussed.