Accounting for Adverse Events Following Immunization in Economic Evaluation: Systematic Review of Economic Evaluations of Pediatric Vaccines Against Pneumococcus, Rotavirus, Human Papillomavirus, Meningococcus and Measles-Mumps-Rubella-Varicella

OBJECTIVES

Economic evaluations of vaccines should accurately represent all relevant economic and health consequences of vaccination, including losses due to adverse events following immunization (AEFI). We investigated to what extent economic evaluations of pediatric vaccines account for AEFI, which methods are used to do so and whether inclusion of AEFI is associated with study characteristics and the vaccine's safety profile.

METHODS

A systematic literature search (MEDLINE, EMBASE, Cochrane Systematic Reviews and Trials, Database of the Centre for Reviews and Dissemination of the University of York, EconPapers, Paediatric Economic Database Evaluation, Tufts New England Cost-Effectiveness Analysis Registry, Tufts New England Global Health CEA, International Network of Agencies for Health Technology Assessment Database) was performed for economic evaluations published between 2014 and 29 April 2021 (date of search) pertaining to the five groups of pediatric vaccines licensed in Europe and the United States since 1998: the human papillomavirus (HPV) vaccines, the meningococcal vaccines (MCV), the measles-mumps-rubella-varicella (MMRV) combination vaccines, the pneumococcal conjugate vaccines (PCV) and the rotavirus vaccines (RV). Rates of accounting for AEFI were calculated, stratified by study characteristics (e.g., region, publication year, journal impact factor, level of industry involvement) and triangulated with the vaccine's safety profile (Advisory Committee on Immunization Practices [ACIP] recommendations and information on safety-related product label changes). The studies accounting for AEFI were analyzed in terms of the methods used to account for both cost and effect implications of AEFI.

RESULTS

We identified 112 economic evaluations, of which 28 (25%) accounted for AEFI. This proportion was significantly higher for MMRV (80%, four out of five evaluations), MCV (61%, 11 out of 18 evaluations) and RV (60%, nine out of 15 evaluations) compared to HPV (6%, three out of 53 evaluations) and PCV (5%, one out of 21 evaluations). No other study characteristics were associated with a study's likelihood of accounting for AEFI. Vaccines for which AEFI were more frequently accounted for also had a higher frequency of label changes and a higher level of attention to AEFI in ACIP recommendations. Nine studies accounted for both the cost and health implications of AEFI, 18 studies considered only costs and one only health outcomes. While the cost impact was usually estimated based on routine billing data, the adverse health impact of AEFI was usually estimated based on assumptions.

DISCUSSION

Although (mild) AEFI were demonstrated for all five studied vaccines, only a quarter of reviewed studies accounted for these, mostly in an incomplete and inaccurate manner. We provide guidance on which methods to use to better quantify the impact of AEFI on both costs and health outcomes. Policymakers should be aware that the impact of AEFI on cost-effectiveness is likely to be underestimated in the majority of economic evaluations.

The cost-effectiveness of bivalent, quadrivalent, and nine-valent HPV vaccination in Asia: a systematic review

PURPOSE

The aim of this study was to systematically review the cost-effectiveness of HPV vaccination in Asia.

METHODS

We performed a systematic review of papers indexed in PubMed, Scopus, and Web of Science covering the period from 1 January 2000 to 13 August 2020.

RESULTS

Sixteen studies were included in the review. Half of them (8 studies) evaluated the cost-effectiveness of HPV vaccination in high-income countries and regions (HICs) while the other eight studies were set in low- and middle-income countries and regions (LMICs). In HICs, the implementation of bivalent, quadrivalent and nine-valent HPV vaccination was all shown to be cost-effective. Most studies (7/8) also showed that it was cost-effective to implement bivalent, quadrivalent, and nine-valent HPV vaccines in LMICs. However, one study concluded that it was not cost-effective to implement bivalent HPV vaccination in Thailand.

CONCLUSION

In general, the implementation of bivalent, quadrivalent and nine-valent HPV vaccination for adolescent girls was cost-effective in both high-income countries and regions and low- and middle-income countries and regions in Asia. Policy makers in HICs could consider expanding the target vaccinated population, while for LMICs it is essential to reduce HPV vaccine price to a level at which the implementation of HPV vaccination is cost-effective.

How to recover lost vaccine acceptance? A multi-center survey on HPV vaccine acceptance in Japan

BACKGROUND

The plummeting acceptance rate of the HPV vaccine in Japan is one of the most disappointing vaccine-related events in recent times. Since 2013, the national HPV vaccine coverage rate fell from more than 70% to less than 1%. This survey investigated parental HPV vaccine acceptance and the factors that influence it.

METHODS

A multi-center survey was conducted in eight hospitals in Nara prefecture, Japan, from July 2019 to March 2020. Parents were asked to answer a series of questions in a survey that included information on the HPV vaccine.

RESULTS

Among the 1884 parents who answered the questionnaire, 21.8% indicated that they had accepted the HPV vaccine even before reading the information provided in the questionnaire. The overall acceptance rate after everyone had read the information increased to 50.2% (p < 0.001). Among those who still did not accept the vaccine after reading the information (N = 925), 26.7% indicated that they might change their mind if more vaccine safety reports were to appear in the mass media; other potentially influencing factors were direct communication from health care providers (35.1%), a recommendation by government (19.5%), and peer behavior (16.8%).

CONCLUSION

The study showed that providing appropriate medical information significantly improves HPV vaccine acceptance. To reverse the loss of HPV vaccine acceptance in Japan, a multi-discipline approach that includes the mass media, health care providers, the government and the general population will be needed.

Alternative New Mono-scaled Quantitative Benefit-Risk Assessment of Human Papillomavirus Vaccine in Japan

BACKGROUND

The human papillomavirus (HPV) vaccine coverage is very low in Japan since the government suspended the active encouragement of the vaccination. We aimed to conduct a benefit-risk assessment of HPV vaccination and explore different consequent scenarios to identify potential improvements to the current Japanese immunization program.

METHODS

To calculate social benefit-risk of HPV vaccine, we used the Markov model to represent the natural history of HPV and adverse events (AEs) using disability-adjusted life year (DALY) as the outcome. Benefits and risks were calculated as the sum of negative and positive outcomes corresponding to all preventable diseases and AEs associated with HPV vaccination, respectively. The benefit-risk balance in 2050 was estimated using published data.

RESULTS

Our model was confirmed by published cervical cancer incidence and mortality rates. The benefit-risk balance in 2050 showed that the most effective scenario was the introduction of 9-valent HPV vaccine targeting female individuals aged 10-29 years for routine vaccination starting in 2020, although there is possibility of increased risks of AEs for the vaccinated age group post resumption of recommendations.

CONCLUSION

Our benefit-risk assessment of HPV vaccine helped estimate various scenarios pertaining to HPV vaccination and identify the best strategy regarding HPV vaccination. This benefit-risk assessment approach may be used for other vaccines and vaccination programs.

Stopping the HPV vaccine crisis in Japan: Quantifying the benefits and risks of HPV vaccination in quality-adjusted life-years for appropriate decision-making

BACKGROUND

The human papilloma virus (HPV) vaccination coverage rate in Japan has dropped dramatically from more than 70% to less than 1% since 2013. With conflicting information and a lack of quantification of the benefits and risks of the HPV vaccine, parents have been hindered in making their decision. We quantified the benefits and risks of the HPV vaccine in terms of quality-adjusted life-years (QALYs), to help their informed decision.

METHOD

A literature search was performed to determine the incidence and burden of each outcome in a decision tree model. The benefits and the risks of the HPV vaccination were determined in QALY change with a sensitivity analysis.

RESULT

The benefits of the HPV vaccine in terms of QALYs gained were 703.72, 14.45, and 30.83/100,000 persons for cervical cancer, cervical intraepithelial neoplasm 3 (CIN 3), and genital warts, respectively. The QALY loss due to acute adverse reactions, chronic adverse reactions without assistance needs, and chronic adverse reactions with assistance needs were 0.07, 5.83, and 5.82/100,000 persons, respectively. The risk/benefit ratio in QALY change in the base case was 0.0156. In all scenarios, the benefit of the HPV vaccine was significantly greater than the risk.

CONCLUSION

The benefits are much greater than the risks, even if it is assumed that all reported adverse events were due to the vaccination. The Japanese government and health care providers should immediately recommend the HPV vaccine to all adolescent girls irrespective of any causal links between the vaccine and reported adverse events.

Cost effectiveness of human papilloma virus vaccination in low and middle income countries: a systematic review of literature

INTRODUCTION

Low and middle income countries (LMICs) bear more than 50% of the current cervical cancer burden over the last decade with linkages to lack of HPV vaccination, high levels of poverty, illiteracy and nonexistent or poor screening programs. Governments of LMICs need enough convincing evidence that HPV vaccination will be more cost-effective in reducing the scourge of cervical cancer.

AREAS COVERED

A systematic review to identify suitable studies from MEDLINE(via PubMed), EMBASE and Electronic search through GOOGLE for original and review articles from 2007 to 2014 on cost-effectiveness of human papilloma virus vaccination of pre-adolescent girls in LMICs was conducted. A total of 19 full articles were finally selected and reviewed after screening out those not consistent with the inclusion and exclusion criteria.

EXPERT COMMENTARY

Most studies on cost-effectiveness of HPV vaccine in LMICs show that lowering cost of HPV vaccination with or without Pap smear screening is cost-effective in areas with high incidence of cervical cancer.