WHO guide on the economic evaluation of influenza vaccination

Acceptability, cost-effectiveness, and capacity of a facility-based seasonal influenza vaccination among high-risk groups: a study protocol in selected tertiary care hospitals of Bangladesh

BACKGROUND

In Bangladesh, seasonal influenza imposes considerable disease and economic burden, especially for those at high-risk of severe disease. The most successful approach for influenza prevention is the administration of a vaccine. Many poor and middle-income nations, including Bangladesh, do not have a national strategy or program in place for seasonal influenza vaccines, despite the World Health Organization's (WHO) advice to prioritize high-risk populations. Additionally, there is a scarcity of substantial data on the cost-effectiveness of seasonal influenza vaccination in these countries. The aim of our study is to determine acceptability, health beliefs, barriers, and intention of receiving influenza vaccine among high-risk populations, assess the cost-effectiveness of implementing a facility-based seasonal influenza vaccination programme, and investigate the required capacity for a potential seasonal influenza vaccination programme.

METHODS

We will undertake this study following STROBE guidelines. We will conduct the study in inpatient and outpatient departments of three selected tertiary-level hospitals leveraging the ongoing hospital-based influenza surveillance (HBIS) platform. The study population will include the WHO-defined four high-risk groups excluding healthcare workers: children six months to eight years, pregnant women, elderly ≥ 60 years, and adults with chronic diseases. We will collect quantitative data on participants' acceptability, health beliefs, barriers, and vaccination intentions using the health belief model (HBM) from patients meeting the criteria for high-risk populations attending two public tertiary-level hospitals. In one of the two public tertiary-level hospitals, we will arrange an influenza vaccination campaign before the influenza season, where the vaccine will be offered free of cost to high-risk patients, and in the second hospital, vaccination will not be offered. Both the vaccinated and unvaccinated participants will then be followed-up once a month for one year to record any influenza-like illness, hospitalization, and death. Additional data for objective two will be collected from patients with symptoms of influenza-like illness (ILI) and severe acute respiratory infection (SARI) at one public and one private hospital to determine both direct and indirect costs associated with influenza illness. We will estimate the required number of influenza vaccines, safe injections, and total storage volume utilizing secondary data. We will use a deterministic Markov decision-analytic model to estimate the cost-effectiveness of facility-based influenza vaccination in Bangladesh.

DISCUSSION

The results of this study will enable the National Immunization Technical Advisory Group and the Ministry of Health & Family Welfare of Bangladesh to decide what steps to take to develop and implement an influenza vaccination strategy targeting high-risk populations.

TRIAL REGISTRATION

The Clinicaltrials.gov registration number is NCT05996549. The registration for the protocol version 2.0 took place in August 2023, with the initial participant being enrolled in March 2022.

Costs and cost-effectiveness of influenza illness and vaccination in low- and middle-income countries: A systematic review from 2012 to 2022

BACKGROUND

Historically, lack of data on cost-effectiveness of influenza vaccination has been identified as a barrier to vaccine use in low- and middle-income countries. We conducted a systematic review of economic evaluations describing (1) costs of influenza illness; (2) costs of influenza vaccination programs; and (3) vaccination cost-effectiveness from low- and middle-income countries to assess if gaps persist that could hinder global implementation of influenza vaccination programs.

METHODS AND FINDINGS

We performed a systematic search in Medline, Embase, Cochrane Library, CINAHL, and Scopus in January 2022 and October 2023 using a combination of the following key words: "influenza" AND "cost" OR "economic." The search included studies with publication years 2012 through 2022. Studies were eligible if they (1) presented original, peer-reviewed findings on cost of illness, cost of vaccination program, or cost-effectiveness of vaccination for seasonal influenza; and (2) included data for at least 1 low- or middle-income country. We abstracted general study characteristics and data specific to each of the 3 study types. Of 54 included studies, 26 presented data on cost-effectiveness, 24 on cost-of-illness, and 5 on program costs. Represented countries were classified as upper-middle income (UMIC; n = 12), lower-middle income (LMIC; n = 7), and low-income (LIC; n = 3). The most evaluated target groups were children (n = 26 studies), older adults (n = 17), and persons with chronic medical conditions (n = 12); fewer studies evaluated pregnant persons (n = 9), healthcare workers (n = 5), and persons in congregate living settings (n = 1). Costs-of-illness were generally higher in UMICs than in LMICs/LICs; however, the highest national economic burden, as a percent of gross domestic product and national health expenditure, was reported from an LIC. Among studies that evaluated the cost-effectiveness of influenza vaccine introduction, most (88%) interpreted at least 1 scenario per target group as either cost-effective or cost-saving, based on thresholds designated in the study. Key limitations of this work included (1) heterogeneity across included studies; (2) restrictiveness of the inclusion criteria used; and (3) potential for missed influenza burden from use of sentinel surveillance systems.

CONCLUSIONS

The 54 studies identified in this review suggest an increased momentum to generate economic evidence about influenza illness and vaccination from low- and middle-income countries during 2012 to 2022. However, given that we observed substantial heterogeneity, continued evaluation of the economic burden of influenza illness and costs/cost-effectiveness of influenza vaccination, particularly in LICs and among underrepresented target groups (e.g., healthcare workers and pregnant persons), is needed. Use of standardized methodology could facilitate pooling across settings and knowledge sharing to strengthen global influenza vaccination programs.

Costs of seasonal influenza vaccine delivery in a pediatric demonstration project for children aged 6-23 months - Nakuru and Mombasa Counties, Kenya, 2019-2021

BACKGROUND

During November 2019-October 2021, a pediatric influenza vaccination demonstration project was conducted in four sub-counties in Kenya. The demonstration piloted two different delivery strategies: year-round vaccination and a four-month vaccination campaign. Our objective was to compare the costs of both delivery strategies.

METHODS

Cost data were collected using standardized questionnaires and extracted from government and project accounting records. We reported total costs and costs per vaccine dose administered by delivery strategy from the Kenyan government perspective in 2021 US$. Costs were separated into financial costs (monetary expenditures) and economic costs (financial costs plus the value of existing resources). We also separated costs by administrative level (national, regional, county, sub-county, and health facility) and program activity (advocacy and social mobilization; training; distribution, storage, and waste management; service delivery; monitoring; and supervision).

RESULTS

The total estimated cost of the pediatric influenza demonstration project was US$ 225,269 (financial) and US$ 326,691 (economic) for the year-round delivery strategy (30,397 vaccine doses administered), compared with US$ 214,753 (financial) and US$ 242,385 (economic) for the campaign strategy (25,404 doses administered). Vaccine purchase represented the largest proportion of costs for both strategies. Excluding vaccine purchase, the cost per dose administered was US$ 1.58 (financial) and US$ 5.84 (economic) for the year-round strategy and US$ 2.89 (financial) and US$ 4.56 (economic) for the campaign strategy.

CONCLUSIONS

The financial cost per dose was 83% higher for the campaign strategy than the year-round strategy due to larger expenditures for advocacy and social mobilization, training, and hiring of surge staff for service delivery. However, the economic cost per dose was more comparable for both strategies (year-round 22% higher than campaign), balanced by higher costs of operating equipment and monitoring activities for the year-round strategy. These delivery cost data provide real-world evidence to inform pediatric influenza vaccine introduction in Kenya.

Socio-demographic determinants of influenza vaccination uptake behavior: A nationwide cross-sectional study in Saudi Arabia

OBJECTIVES

To investigate the sociodemographic determinants of flu vaccine uptake among the Saudi population.

METHODS

A nationwide cross-sectional study was carried out in Saudi Arabia in December 2020, and 1,650 participants took the survey. Data were collected electronically using a structured questionnaire. Logistic regression analysis was carried out to establish the association between vaccine uptake behavior and sociodemographic characteristics of the study participants.

RESULTS

Out of the 1650 participants, 31.5% reported having received the flu vaccine during the 2019-2020 flu season. The logistic regression analysis showed that age above 45 years (adjusted odds ratio [aOR]=2.20, 95% confidence interval [CI]: [1.15-3.05], p=0.002), being married (aOR=1.75, 95% CI: [1.28-3.51], p=0.001), and having a postgraduate degree (aOR=1.51, 95% CI: [1.05-2.23], p=0.044) were significant factors associated with higher vaccine uptake. The study also showed that the perceived risk of getting the flu (aOR=2.15, 95% CI: [1.30-5.72], p=0.001) and knowledge regarding the vaccine (aOR=1.71, 95% CI: [1.08-4.22], p=0.001) were significant factors associated with vaccine uptake.

CONCLUSION

The findings suggest that efforts to increase flu vaccine uptake should focus on increasing awareness and education regarding the benefits of vaccination, particularly among young individuals.

Influenza Vaccination Implementation in Sri Lanka: A Cost-Effectiveness Analysis

Influenza causes an estimated 3 to 5 million cases of severe illness annually, along with substantial morbidity and mortality, particularly in low- and middle-income countries (LMICs). Currently, Sri Lanka has no influenza vaccination policies and does not offer vaccination within the public healthcare sector. Therefore, we performed a cost-effectiveness analysis of influenza vaccine implementation for the Sri Lankan population. We designed a static Markov model that followed a population cohort of Sri Lankans in three age groups, 0-4, 5-64, and 65+ years, through two potential scenarios: trivalent inactivated vaccination (TIV) and no TIV across twelve-monthly cycles using a governmental perspective at the national level. We also performed probabilistic and one-way sensitivity analyses to identify influential variables and account for uncertainty. The vaccination model arm reduced influenza outcomes by 20,710 cases, 438 hospitalizations, and 20 deaths compared to no vaccination in one year. Universal vaccination became cost-effective at approximately 98.01% of Sri Lanka's 2022 GDP per capita (incremental cost-effectiveness ratio = 874,890.55 Rs/DALY averted; 3624.84 USD/DALY averted). Results were most sensitive to the vaccine coverage in the 5-64-year-old age group, the cost of the influenza vaccine dose in the 5-64-years-old age group, vaccine effectiveness in the under-5-years-old age group, and the vaccine coverage in the under-5-years-old age group. No value for a variable within our estimated ranges resulted in ICERs above Rs. 1,300,000 (USD 5386.15) per DALY adverted. Providing influenza vaccines was considered highly cost-effective compared to no vaccines. However, large-scale national studies with improved data are needed to better inform estimates and determine the impact of vaccination implementation.

A comprehensive review of official discount rates in guidelines of health economic evaluations over time: the trends and roots

BACKGROUND

The question of discounting in health economics is anything but settled, so much so that a section of the Health Technology Assessment (HTA) guidelines is devoted to it.

OBJECTIVE

This study aimed to review the trend of the value of the official discount rates (DRs) of costs and health outcomes and their roots worldwide.

METHODS

Four methods were combined to identify official DRs over time globally. These methods included a systematic review of the HTA/pharmacoeconomic/health economic evaluation guidelines, a review of methodological documents or guidelines accessible on the websites of HTA organizations, and two separated reviews of the websites of the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) and the Guide to Health Economic Analysis and Research (GEAR).

RESULTS

Our systematic search eventually yielded 339 documents from the literature, 35 links from the website of the HTA organizations, 51 documents from the website of the ISPOR, and 29 documents from the website of the GEAR. These documents referred to 48 countries over 30 years and 43 transnational guidelines over 43 years. DRs of 3% and 5% had the most frequent value. Among them, 38 countries always used an equal DR of costs and health outcomes. We categorized the rationales for selecting DRs into eight groups for the national documents and six groups for the transnational documents.

CONCLUSION

The comparability approach was the most frequent rationale for choosing the DR in national and transnational guidelines. The value of DR of costs and health outcomes ranged from zero to 10% over the years, but the most common values were 3% and 5%, mainly arising from the comparability approach chosen. Several transnational guidelines have suggested a specific DR without taking into account countries' economic conditions. It is useful to establish a specific guideline for calculating and updating the DR of the health sector in each country.

Using Health Economics to Inform Immunization Policy Across All Levels of Government

Publicly funded immunization programs have grown in both complexity and scope, resulting in increased costs and more complex programmatic decision making. Economic evaluations can provide crucial information to support informed decision making. While very few countries have National Immunization Technical Advisory Groups that analyze economic information, many have started to develop processes for this purpose. Since these guidelines are being developed at the national level, we propose that regional jurisdictions, especially those responsible for healthcare (e.g., provinces, territories, states), need clear processes for incorporating this information into their immunization decision making and program implementation. We interviewed Canadian vaccine experts involved in provincial vaccine policy decision making to identify current practices, perceptions, and recommendations around incorporating economic analysis into that process. Based on these interviews, we make five recommendations: (1) economic evidence should be routinely incorporated into the decision making process; (2) economic experts should sit on, or be available to, regional advisory committees; (3) efforts should be made to build on regional expertise by increasing educational opportunities on economic evaluation; (4) processes should include guidelines for when economic analysis is not required; and (5) clarification on the role of regional advisory groups in economic analysis is needed in relation to national expertise. The information presented here provides a starting point for regional health policy experts and decision makers to work collaboratively with national partners to create transparent and effective approaches to incorporating economic analysis into vaccine decision making.

Economic Evaluations of Magnetic Resonance Image-Guided Radiotherapy (MRIgRT): A Systematic Review

OBJECTIVES

This review systematically summarizes the evidence on the economic impact of magnetic resonance image-guided RT (MRIgRT).

METHODS

We systematically searched INAHTA, MEDLINE, and Scopus up to March 2022 to retrieve health economic studies. Relevant data were extracted on study type, model inputs, modeling methods and economic results.

RESULTS

Five studies were included. Two studies performed a full economic assessment to compare the cost-effectiveness of MRIgRT with other forms of image-guided radiation therapy. One study performed a cost minimization analysis and two studies performed an activity-based costing, all comparing MRIgRT with X-ray computed tomography image-guided radiation therapy (CTIgRT). Prostate cancer was the target condition in four studies and hepatocellular carcinoma in one. Considering the studies with a full economic assessment, MR-guided stereotactic body radiation therapy was found to be cost effective with respect to CTIgRT or conventional or moderate hypofractionated RT, even with a low reduction in toxicity. Conversely, a greater reduction in toxicity is required to compete with extreme hypofractionated RT without MR guidance.

CONCLUSIONS

This review highlights the great potential of MRIgRT but also the need for further evidence, especially for late toxicity, whose reduction is expected to be the real added value of this technology.

An Economic Evaluation of the Adjuvanted Quadrivalent Influenza Vaccine Compared with Standard-Dose Quadrivalent Influenza Vaccine in the Spanish Older Adult Population

Standard-dose quadrivalent influenza vaccines (QIV) are designed to provide protection against all four influenza strains. Adjuvanted QIV (aQIV), indicated for individuals aged 65+ years, combines MF59^® adjuvant (an oil-in-water emulsion of squalene oil) with a standard dose of antigen, and is designed to produce stronger and longer immune response, especially in the elderly where immunosenescence reduces vaccine effectiveness. This study evaluated the cost-effectiveness of aQIV vs. egg-based standard-dose QIV (QIVe) in the elderly population, from the payer and societal perspective in Spain. A dynamic transmission model, which accounts for herd protection, was used to predict the number of medically attended infections in Spain. A decision tree structure was used to forecast influenza-related costs and benefits. Influenza-related probabilities of outpatient visit, hospitalization, work absenteeism, mortality, and associated utilities and costs were extracted from Spanish and European published literature. Relative vaccine effectiveness (rVE) was sourced from two different meta-analyses: the first meta-analysis was informed by laboratory-confirmed influenza studies only, resulting in a rVE = 34.6% (CI95% 2-66%) in favor of aQIV; the second meta-analysis included real world evidence influenza-related medical encounters outcomes, resulting in a rVE = 13.9% (CI95% 4.2-23.5%) in benefit of aQIV. All costs were expressed in 2021 euros. Results indicate that replacing QIVe with aQIV in the Spanish elderly population would prevent on average 43,664 influenza complicated cases, 1111 hospitalizations, and 569 deaths (with a rVE = 34.6%) or 19,104 influenza complicated cases, 486 hospitalizations, and 252 deaths (with a rVE = 13.9%). When the rVE of aQIV vs. QIVe is 34.6%, the incremental cost per quality adjusted life years (QALY) gained was €2240 from the payer; from the societal perspective, aQIV was cost saving compared with QIVe. If the rVE was 13.9%, the incremental cost per QALY was €6694 and €3936 from the payer and societal perspective, respectively. Sensitivity analyses validated the robustness of these findings. Results indicate that replacing QIVe with aQIV in the Spanish elderly population is a cost-effective strategy for the Spanish healthcare system.

Cost-Effectiveness of Extending the National Influenza Vaccination Program in South Korea: Does Vaccination of Older Adults Provide Health Benefits to the Entire Population?

The South Korean government has successfully improved influenza vaccination coverage for individuals aged 65 years or older as part of its National Immunization Program (NIP). Those aged 50–64 years without funded vaccination care have significantly lower vaccination rates and face a substantial risk of influenza-related complications. We use a dynamic epidemiological and economic model to investigate the cost-effectiveness of expanding the universal vaccine fund to include those aged 50–64. The epidemiological model is estimated using the susceptibility-infection-recovery model and influenza and influenza-like illness incidence rates, which were calculated by the National Health Insurance Service–National Sample Cohort from the 2008/09 to 2012/13 influenza seasons but excluding the 2009/10 season for pandemic influenza A (H1N1). The decision tree economic model is assessed from societal and healthcare sector perspectives. The proposed policy would eliminate 340,000 annual influenza cases and prevent 119 unnecessary deaths. From a societal perspective, the proposed policy would reduce costs by USD 68 million. From a healthcare perspective, the cost is USD 4318 per quality-adjusted life years. Within the study range, sensitivity analyses found consistent cost-effectiveness results. The influenza vaccine for adults aged 50–64 appears to be cost-saving or cost-effective and, thus, should be considered for the NIP.

Recent Progress in Recombinant Influenza Vaccine Development Toward Heterosubtypic Immune Response

Flu, a viral infection caused by the influenza virus, is still a global public health concern with potential to cause seasonal epidemics and pandemics. Vaccination is considered the most effective protective strategy against the infection. However, given the high plasticity of the virus and the suboptimal immunogenicity of existing influenza vaccines, scientists are moving toward the development of universal vaccines. An important property of universal vaccines is their ability to induce heterosubtypic immunity, i.e., a wide immune response coverage toward different influenza subtypes. With the increasing number of studies and mounting evidence on the safety and efficacy of recombinant influenza vaccines (RIVs), they have been proposed as promising platforms for the development of universal vaccines. This review highlights the current progress and advances in the development of RIVs in the context of heterosubtypic immunity induction toward universal vaccine production. In particular, this review discussed existing knowledge on influenza and vaccine development, current hemagglutinin-based RIVs in the market and in the pipeline, other potential vaccine targets for RIVs (neuraminidase, matrix 1 and 2, nucleoprotein, polymerase acidic, and basic 1 and 2 antigens), and deantigenization process. This review also provided discussion points and future perspectives in looking at RIVs as potential universal vaccine candidates for influenza.

Costs of seasonal influenza vaccination in South Africa

Background

Influenza accounts for a substantial number of deaths and hospitalisations annually in South Africa. To address this disease burden, the South African National Department of Health introduced a trivalent inactivated influenza vaccination programme in 2010.

Methods

We adapted and populated the WHO Seasonal Influenza Immunization Costing Tool (WHO SIICT) with country‐specific data to estimate the cost of the influenza vaccination programme in South Africa. Data were obtained through key‐informant interviews at different levels of the health system and through a review of existing secondary data sources. Costs were estimated from a public provider perspective and expressed in 2018 prices. We conducted scenario analyses to assess the impact of different levels of programme expansion and the use of quadrivalent vaccines on total programme costs.

Results

Total financial and economic costs were estimated at approximately USD 2.93 million and USD 7.91 million, respectively, while financial and economic cost per person immunised was estimated at USD 3.29 and USD 8.88, respectively. Expanding the programme by 5% and 10% increased economic cost per person immunised to USD 9.36 and USD 9.52 in the two scenarios, respectively. Finally, replacing trivalent inactivated influenza vaccine (TIV) with quadrivalent vaccine increased financial and economic costs to USD 4.89 and USD 10.48 per person immunised, respectively.

Conclusion

We adapted the WHO SIICT and provide estimates of the total costs of the seasonal influenza vaccination programme in South Africa. These estimates provide a basis for planning future programme expansion and may serve as inputs for cost‐effectiveness analyses of seasonal influenza vaccination programmes.

The Economic Burden of Influenza-Like Illness among Children, Chronic Disease Patients, and the Elderly in China: A National Cross-Sectional Survey

Background: The disease burden of seasonal influenza is substantial in China, while there is still a lack of nationwide economic burden estimates. This study aims to examine influenza-like illness (ILI) prevalence, healthcare-seeking behaviors, economic impact of ILI, and its influencing factors among three priority groups during the 2018–19 influenza season. Methods: From August to October 2019, 6668 children’s caregivers, 1735 chronic disease patients, and 3849 elderly people were recruited from 10 provinces in China to participate in an on-site survey. The economic burden of ILI consisted of direct (medical or non-medical) and indirect burdens, and a two-part model was adopted to predict the influencing factors of total economic burden. Results: There were 45.73% children, 16.77% chronic disease patients, and 12.70% elderly people reporting ILI, and most participants chose outpatient service or over-the-counter (OTC) medication after ILI. The average economic burden was CNY 1647 (USD 237.2) for children, CNY 951 (USD 136.9) for chronic disease patients, and CNY 1796 (USD 258.6) for the elderly. Two-part regression showed that age, gender, whether the only child in the family, region, and household income were important predictors of ILI economic burden among children, while age, region, place of residence, basic health insurance, and household income were significant predictors of ILI economic burden among chronic disease patients and the elderly. Conclusions: A large economic burden of ILI was highlighted, especially among the elderly with less income and larger medical burdens, as well as children, with higher prevalence and higher self-payment ratio. It is important to adopt targeted interventions for high-risk groups, and this study can help national-level decision-making on the introduction of influenza vaccination as a public health project.

Inclusion of Safety-Related Issues in Economic Evaluations for Seasonal Influenza Vaccines: A Systematic Review

(1) Background: Vaccines for seasonal influenza are a good preventive and cost-effective strategy. However, it is unknown if and how these economic evaluations include the adverse events following immunization (AEFI), and what the impact of such inclusion is on the health economic outcomes. (2) Methods: We searched the literature, up to January 2020, to identify economic evaluations of seasonal influenza vaccines that considered AEFIs. The review protocol was published in PROSPERO (CDR42017058523). (3) Results: A total of 52 economic evaluations considered AEFI-related parameters in their analyses, reflecting 16% of the economic evaluations on seasonal influenza vaccines in the initial study selection. Most studies used the societal perspective (64%) and evaluated vaccination of children (37%). Where considered, studies included direct medical costs of AEFIs (90%), indirect costs (27%), and disutilities/quality-adjusted life years loss due to AEFIs (37%). The majority of these studies accounted for the effects of the costs of AEFI on cost-effectiveness for Guillain–Barré syndrome. In those papers allowing cost share estimation, direct medical cost of AFEIs was less than 2% of total direct costs. (4) Conclusions: Although the overall impact of AEFIs on the cost-effectiveness outcomes was found to be low, we urge their inclusion in economic evaluations of seasonal influenza vaccines to reflect comprehensive reports for the decision makers and end-users of the vaccination strategies.

Optimising Vaccine Dose in Inoculation against SARS-CoV-2, a Multi-Factor Optimisation Modelling Study to Maximise Vaccine Safety and Efficacy

Developing a vaccine against the global pandemic SARS-CoV-2 is a critical area of active research. Modelling can be used to identify optimal vaccine dosing; maximising vaccine efficacy and safety and minimising cost. We calibrated statistical models to published dose-dependent seroconversion and adverse event data of a recombinant adenovirus type-5 (Ad5) SARS-CoV-2 vaccine given at doses 5.0 × 10¹⁰, 1.0 × 10¹¹ and 1.5 × 10¹¹ viral particles. We estimated the optimal dose for three objectives, finding: (A) the minimum dose that may induce herd immunity, (B) the dose that maximises immunogenicity and safety and (C) the dose that maximises immunogenicity and safety whilst minimising cost. Results suggest optimal dose [95% confidence interval] in viral particles per person was (A) 1.3 × 10¹¹ [0.8–7.9 × 10¹¹], (B) 1.5 × 10¹¹ [0.3–5.0 × 10¹¹] and (C) 1.1 × 10¹¹ [0.2–1.5 × 10¹¹]. Optimal dose exceeded 5.0 × 10¹⁰ viral particles only if the cost of delivery exceeded £0.65 or cost per 10¹¹ viral particles was less than £6.23. Optimal dose may differ depending on the objectives of developers and policy-makers, but further research is required to improve the accuracy of optimal-dose estimates.

Cost-Effectiveness of Pediatric Influenza Vaccination in The Netherlands

OBJECTIVE

This study evaluates the cost-effectiveness of extending the Dutch influenza vaccination program for elderly and medical high-risk groups to include pediatric influenza vaccination, taking indirect protection into account.

METHODS

An age-structured dynamic transmission model was used that was calibrated to influenza-associated GP visits over 4 seasons (2010-2011 to 2013-2014). The clinical and economic impact of different pediatric vaccination strategies were compared over 20 years, varying the targeted age range, the vaccine type for children or elderly and high-risk groups. Outcome measures include averted symptomatic infections and deaths, societal costs and quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. Costs and QALYs were discounted at 4% and 1.5% annually.

RESULTS

At an assumed coverage of 50%, adding pediatric vaccination for 2- to 17-year-olds with quadrivalent live-attenuated vaccine to the current vaccination program for elderly and medical high-groups with quadrivalent inactivated vaccine was estimated to avert, on average, 401 820 symptomatic cases and 72 deaths per year. Approximately half of averted symptomatic cases and 99% of averted deaths were prevented in other age groups than 2- to 17-year-olds due to herd immunity. The cumulative discounted 20-year economic impact was 35 068 QALYs gained and €1687 million saved, that is, the intervention was cost-saving. This vaccination strategy had the highest probability of being the most cost-effective strategy considered, dominating pediatric strategies targeting 2- to 6-year-olds or 2- to 12-year-olds or strategies with trivalent inactivated vaccine.

CONCLUSION

Modeling indicates that introducing pediatric influenza vaccination in The Netherlands is cost-saving, reducing the influenza-related disease burden substantially.

A cost/benefit analysis of clinical trial designs for COVID-19 vaccine candidates

We compare and contrast the expected duration and number of infections and deaths averted among several designs for clinical trials of COVID-19 vaccine candidates, including traditional and adaptive randomized clinical trials and human challenge trials. Using epidemiological models calibrated to the current pandemic, we simulate the time course of each clinical trial design for 756 unique combinations of parameters, allowing us to determine which trial design is most effective for a given scenario. A human challenge trial provides maximal net benefits-averting an additional 1.1M infections and 8,000 deaths in the U.S. compared to the next best clinical trial design-if its set-up time is short or the pandemic spreads slowly. In most of the other cases, an adaptive trial provides greater net benefits.

From trivalent to quadrivalent influenza vaccines: Public health and economic burden for different immunization strategies in Spain

PURPOSE

Quadrivalent influenza vaccine (QIV) includes the same strains as trivalent influenza vaccine (TIV) plus an additional B strain of the other B lineage. The aim of the study was to analyse the public health and economic impact of replacing TIV with QIV in different scenarios in Spain.

METHODS

A dynamic transmission model was developed to estimate the number of influenza B cases prevented under TIV and QIV strategies (<65 years (high risk) and ≥65 years). This model considers cross-protective immunity induced by different lineages of influenza B. The output of the transmission model was used as input for a decision tree model that estimated the economic impact of switching TIV to QIV. The models were populated with Spanish data whenever possible. Deterministic univariate and probabilistic multivariate sensitivity analyses were performed.

RESULTS

Replacing TIV with QIV in all eligible patients with current vaccine coverage in Spain may have prevented 138,707 influenza B cases per season and, therefore avoided 10,748 outpatient visits, 3,179 hospitalizations and 192 deaths. The replacement could save €532,768 in outpatient visit costs, €13 million in hospitalization costs, and €3 million in costs of influenza-related deaths per year. An additional €5 million costs associated with productivity loss could be saved per year, from the societal perspective. The budget impact from societal perspective would be €6.5 million, and the incremental cost-effectiveness ratio (ICER) €1,527 per quality-adjusted life year (QALY). Sensitivity analyses showed robust results. In additional scenarios, QIV also showed an impact at public health level reducing influenza B related cases, outpatient visits, hospitalizations and deaths.

CONCLUSIONS

Our results show public health and economic benefits for influenza prevention with QIV. It would be an efficient intervention for the Spanish National Health Service with major health benefits especially in the population ≥65-year.

Program cost analysis of influenza vaccination of health care workers in Albania

BACKGROUND

Since 2012, WHO has recommended influenza vaccination for health care workers (HCWs), which has different costs than routine infant immunization; however, few cost estimates exist from low- and middle-income countries. Albania, a middle-income country, has self-procured influenza vaccine for some HCWs since 2014, supplemented by vaccine donations since 2016 through the Partnership for Influenza Vaccine Introduction (PIVI). We conducted a cost analysis of HCW influenza vaccination in Albania to inform scale-up and sustainability decisions.

METHODS

We used the WHO's Seasonal Influenza Immunization Costing Tool (SIICT) micro-costing approach to estimate incremental costs from the government perspective of facility-based vaccination of HCWs in Albania with trivalent inactivated influenza vaccine for the 2018-19 season based on 2016-17 season data from administrative records, key informant consultations, and a convenience sample of site visits. Scenario analyses varied coverage, vaccine presentation, and vaccine prices.

RESULTS

In the baseline scenario, 13,377 HCWs (70% of eligible HCWs) would be vaccinated at an incremental financial cost of US$61,296 and economic cost of US$161,639. Vaccine and vaccination supplies represented the largest share of financial (89%) and economic costs (44%). Per vaccinated HCW financial cost was US$4.58 and economic cost was US$12.08 including vaccine and vaccination supplies (US$0.49 and US$6.76 respectively without vaccine and vaccination supplies). Scenarios with higher coverage, pre-filled syringes, and higher vaccine prices increased total economic and financial costs, although the economic cost per HCW vaccinated decreased with higher coverage as some costs were spread over more HCWs. Across all scenarios, economic costs were <0.07% of Albania's estimated government health expenditure, and <5.07% of Albania's estimated immunization program economic costs.

CONCLUSIONS

Cost estimates can help inform decisions about scaling up influenza vaccination for HCWs and other risk groups.

Use of adjuvanted trivalent influenza vaccine in older-age adults: a systematic review of economic evidence

Seasonal influenza is a very common disease. Yearly vaccination of at-risk population groups is a well-recognized cost-effective/cost-saving preventive measure. It is, however, unclear which available alternative has the most favorable economic profile. Some available options are: trivalent (TIV) and quadrivalent (QIV) inactivated vaccines, adjuvanted TIV (aTIV). Because of immunosenescence, aTIV has been specifically developed for elderly. The present study aimed at assessing the available evidence of aTIV use in elderly from the economic perspective. A systematic literature review targeting aTIV economic evaluations in adults aged ≥65 years was performed using Medline via Ovid, Embase, DARE and NHS/EED. Of a total of 3,654 papers screened, 18 studies (13 full papers, 5 conference abstracts) were included. It emerged that compared with both non-vaccination or non-adjuvanted vaccines, aTIV was cost-effective or cost-saving. The vaccinations strategies incorporating aTIV based on age and/or risk profile are associated with the most favorable economic outcomes.