Contribution of vaccination to improved survival and health: modelling 50 years of the Expanded Programme on Immunization.

BACKGROUND: WHO, as requested by its member states, launched the Expanded Programme on Immunization (EPI) in 1974 to make life-saving vaccines available to all globally. To mark the 50-year anniversary of EPI, we sought to quantify the public health impact of vaccination globally since the programme's inception. METHODS: In this modelling study, we used a suite of mathematical and statistical models to estimate the global and regional public health impact of 50 years of vaccination against 14 pathogens in EPI. For the modelled pathogens, we considered coverage of all routine and supplementary vaccines delivered since 1974 and estimated the mortality and morbidity averted for each age cohort relative to a hypothetical scenario of no historical vaccination. We then used these modelled outcomes to estimate the contribution of vaccination to globally declining infant and child mortality rates over this period. FINDINGS: Since 1974, vaccination has averted 154 million deaths, including 146 million among children younger than 5 years of whom 101 million were infants younger than 1 year. For every death averted, 66 years of full health were gained on average, translating to 10·2 billion years of full health gained. We estimate that vaccination has accounted for 40% of the observed decline in global infant mortality, 52% in the African region. In 2024, a child younger than 10 years is 40% more likely to survive to their next birthday relative to a hypothetical scenario of no historical vaccination. Increased survival probability is observed even well into late adulthood. INTERPRETATION: Since 1974 substantial gains in childhood survival have occurred in every global region. We estimate that EPI has provided the single greatest contribution to improved infant survival over the past 50 years. In the context of strengthening primary health care, our results show that equitable universal access to immunisation remains crucial to sustain health gains and continue to save future lives from preventable infectious mortality. FUNDING: WHO.

The cost and cost-effectiveness of novel tuberculosis vaccines in low- and middle-income countries: A modeling study.

BACKGROUND: Tuberculosis (TB) is preventable and curable but eliminating it has proven challenging. Safe and effective TB vaccines that can rapidly reduce disease burden are essential for achieving TB elimination. We assessed future costs, cost-savings, and cost-effectiveness of introducing novel TB vaccines in low- and middle-income countries (LMICs) for a range of product characteristics and delivery strategies. METHODS AND FINDINGS: We developed a system of epidemiological and economic models, calibrated to demographic, epidemiological, and health service data in 105 LMICs. For each country, we assessed the likely future course of TB-related outcomes under several vaccine introduction scenarios, compared to a "no-new-vaccine" counterfactual. Vaccine scenarios considered 2 vaccine product profiles (1 targeted at infants, 1 at adolescents/adults), both assumed to prevent progression to active TB. Key economic inputs were derived from the Global Health Cost Consortium, World Health Organization (WHO) patient cost surveys, and the published literature. We estimated the incremental impact of vaccine introduction for a range of health and economic outcomes. In the base-case, we assumed a vaccine price of $4.60 and used a 1× per-capita gross domestic product (GDP) cost-effectiveness threshold (both varied in sensitivity analyses). Vaccine introduction was estimated to require substantial near-term resources, offset by future cost-savings from averted TB burden. From a health system perspective, adolescent/adult vaccination was cost-effective in 64 of 105 LMICs. From a societal perspective (including productivity gains and averted patient costs), adolescent/adult vaccination was projected to be cost-effective in 73 of 105 LMICs and cost-saving in 58 of 105 LMICs, including 96% of countries with higher TB burden. When considering the monetized value of health gains, we estimated that introduction of an adolescent/adult vaccine could produce $283 to 474 billion in economic benefits by 2050. Limited data availability required assumptions and extrapolations that may omit important country-level heterogeneity in epidemiology and costs. CONCLUSIONS: TB vaccination would be highly impactful and cost-effective in most LMICs. Further efforts are needed for future development, adoption, and implementation of novel TB vaccines.

The Full Value of Vaccine Assessments (FVVA): a framework for assessing and communicating the value of vaccines for investment and introduction decision-making.

BACKGROUND: Several economic obstacles can deter the development and use of vaccines. This can lead to limited product options for some diseases, delays in new product development, and inequitable access to vaccines. Although seemingly distinct, these obstacles are actually interrelated and therefore need to be addressed through a single over-arching strategy encompassing all stakeholders. METHODS: To help overcome these obstacles, we propose a new approach, the Full Value of Vaccines Assessments (FVVA) framework, to guide the assessment and communication of the value of a vaccine. The FVVA framework is designed to facilitate alignment across key stakeholders and to enhance decision-making around investment in vaccine development, policy-making, procurement, and introduction, particularly for vaccines intended for use in low- and middle-income countries. RESULTS: The FVVA framework has three key elements. First, to enhance assessment, existing value-assessment methods and tools are adapted to include broader benefits of vaccines as well as opportunity costs borne by stakeholders. Second, to improve decision-making, a deliberative process is required to recognize the agency of stakeholders and to ensure country ownership of decision-making and priority setting. Third, the FVVA framework provides a consistent and evidence-based approach that facilitates communication about the full value of vaccines, helping to enhance alignment and coordination across diverse stakeholders. CONCLUSIONS: The FVVA framework provides guidance for stakeholders organizing global-level efforts to promote investment in vaccines that are priorities for LMICs. By providing a more holistic view of the benefits of vaccines, its application also has the potential to encourage greater take-up by countries, thereby leading to more sustainable and equitable impacts of vaccines and immunization programmes.

Costs of Immunization Programs for 10 Vaccines in 94 Low- and Middle-Income Countries From 2011 to 2030.

OBJECTIVES: Understanding the level of investment needed for the 2021-2030 decade is important as the global community faces the next strategic period for vaccines and immunization programs. To assist with this goal, we estimated the aggregate costs of immunization programs for ten vaccines in 94 low- and middle-income countries from 2011 to 2030. METHOD: We calculated vaccine, immunization delivery and stockpile costs for 94 low- and middle-income countries leveraging the latest available data sources. We conducted scenario analyses to vary assumptions about the relationship between delivery cost and coverage as well as vaccine prices for fully self-financing countries. RESULTS: The total aggregate cost of immunization programs in 94 countries for 10 vaccines from 2011 to 2030 is $70.8 billion (confidence interval: $56.6-$93.3) under the base case scenario and $84.1 billion ($72.8-$102.7) under an incremental delivery cost scenario, with an increasing trend over two decades. The relative proportion of vaccine and delivery costs for pneumococcal conjugate, human papillomavirus, and rotavirus vaccines increase as more countries introduce these vaccines. Nine countries in accelerated transition phase bear the highest burden of the costs in the next decade, and uncertainty with vaccine prices for the 17 fully self-financing countries could lead to total costs that are 1.3-13.1 times higher than the base case scenario. CONCLUSION: Resource mobilization efforts at the global and country levels will be needed to reach the level of investment needed for the coming decade. Global-level initiatives and targeted strategies for transitioning countries will help ensure the sustainability of immunization programs.

Economic Benefits of Immunization for 10 Pathogens in 94 Low- and Middle-Income Countries From 2011 to 2030 Using Cost-of-Illness and Value-of-Statistical-Life Approaches.

OBJECTIVES: Vaccination has prevented millions of deaths and cases of disease in low- and middle-income countries (LMICs). During the Decade of Vaccines (2011-2020), international organizations, including the World Health Organization and Gavi, the Vaccine Alliance, focused on new vaccine introduction and expanded coverage of existing vaccines. As Gavi, other organizations, and country governments look to the future, we aimed to estimate the economic benefits of immunization programs made from 2011 to 2020 and potential gains in the future decade. METHODS: We used estimates of cases and deaths averted by vaccines against 10 pathogens in 94 LMICs to estimate the economic value of immunization. We applied 3 approaches-cost of illness averted (COI), value of statistical life (VSL), and value of statistical life-year (VSLY)-to estimate observable and unobservable economic benefits between 2011 and 2030. RESULTS: From 2011 to 2030, immunization would avert $1510.4 billion ($674.3-$2643.2 billion) (2018 USD) in costs of illness in the 94 modeled countries, compared with the counterfactual of no vaccination. Using the VSL approach, immunization would generate $3436.7 billion ($1615.8-$5657.2 billion) in benefits. Applying the VSLY approach, $5662.7 billion ($2547.2-$9719.4) in benefits would be generated. CONCLUSION: Vaccination has generated significant economic benefits in LMICs in the past decade. To reach predicted levels of economic benefits, countries and international donor organizations need to meet coverage projections outlined in the Gavi Operational Forecast. Estimates generated using the COI, VSL, or VSLY approach may be strategically used by donor agencies, decision makers, and advocates to inform investment cases and advocacy campaigns.

A Scoping Review of Investment Cases for Vaccines and Immunization Programs.

BACKGROUND: Many investment cases have recently been published intending to show the value of new health investments, but without consistent methodological approaches. OBJECTIVES: To conduct a scoping review of existing investment cases (using vaccines and immunization programs as an example), identify common characteristics that define these investment cases, and examine their role within the broader context of the vaccine development and introduction. METHODS: A systematic search was conducted from January 1980 to November 2017 to identify investment cases in the area of vaccines and immunization programs from gray literature and electronic bibliographic databases. Investment case outcomes, objectives, key variables, target audiences, and funding sources were extracted and analyzed according to their reporting frequency. RESULTS: We found 24 investment cases, and most of them aim to provide information for decisions (12 cases) or advocate for a specific agenda (9 cases). Outcomes presented fell into 4 broad categories-burden of disease, cost of investment, impact of investment, and other considerations for implementation. Number of deaths averted (70%), incremental cost-effectiveness ratios (67%), and reduction in health and socioeconomic inequalities (54%) were the most frequently reported outcome measures for impact of investment. Health system capacity (79%) and vaccine financing landscape (75%) were the most common considerations for implementation. A sizable proportion (41.4%) of investment cases did not reveal their funding sources. CONCLUSIONS: This review describes information that is critical to decision making about resource mobilization and allocation concerning vaccines. Global efforts to harmonize investment cases more broadly will increase transparency and comparability.

A Practical Guide to Full Value of Vaccine Assessments.

Articulating the wide range of health, social and economic benefits that vaccines offer may help to overcome obstacles in the vaccine development pipeline. A framework to guide the assessment and communication of the value of a vaccine-the Full Value of Vaccine Assessment (FVVA)-has been developed by the WHO. The FVVA framework offers a holistic assessment of the value of vaccines, providing a synthesis of evidence to inform the public health need of a vaccine, describing the supply and demand aspects, its market and its impact from a health, financial and economic perspective. This paper provides a practical guide to how FVVAs are developed and used to support investment in vaccines, ultimately leading to sustained implementation in countries. The FVVA includes a range of elements that can be broadly categorised as synthesis, vaccine development narrative and defining vaccine impact and value. Depending on the features of the disease/vaccine in question, different elements may be emphasised; however, a standardised set of elements is recommended for each FVVA. The FVVA should be developed by an expert group who represent a range of stakeholders, perspectives and geographies and ensure a fair, coherent and evidence-based assessment of vaccine value.

Estimating the Impact of Vaccination Campaigns on Measles Transmission in Somalia.

Somalia is a complex and fragile setting with a demonstrated potential for disruptive, high-burden measles outbreaks. In response, since 2018, Somalian authorities have partnered with UNICEF and the WHO to implement measles vaccination campaigns across the country. In this paper, we create a Somalia-specific model of measles transmission based on a comprehensive epidemiological dataset including case-based surveillance, vaccine registries, and serological surveys. We use this model to assess the impact of these campaign interventions on Somalian's measles susceptibility, showing, for example, that across the roughly 10 million doses delivered, 1 of every 5 immunized a susceptible child. Finally, we use the model to explore a counter-factual epidemiology without the 2019-2020 campaigns, and we estimate that those interventions prevented over 10,000 deaths.

Estimating the health effects of COVID-19-related immunisation disruptions in 112 countries during 2020-30: a modelling study.

BACKGROUND: There have been declines in global immunisation coverage due to the COVID-19 pandemic. Recovery has begun but is geographically variable. This disruption has led to under-immunised cohorts and interrupted progress in reducing vaccine-preventable disease burden. There have, so far, been few studies of the effects of coverage disruption on vaccine effects. We aimed to quantify the effects of vaccine-coverage disruption on routine and campaign immunisation services, identify cohorts and regions that could particularly benefit from catch-up activities, and establish if losses in effect could be recovered. METHODS: For this modelling study, we used modelling groups from the Vaccine Impact Modelling Consortium from 112 low-income and middle-income countries to estimate vaccine effect for 14 pathogens. One set of modelling estimates used vaccine-coverage data from 1937 to 2021 for a subset of vaccine-preventable, outbreak-prone or priority diseases (ie, measles, rubella, hepatitis B, human papillomavirus [HPV], meningitis A, and yellow fever) to examine mitigation measures, hereafter referred to as recovery runs. The second set of estimates were conducted with vaccine-coverage data from 1937 to 2020, used to calculate effect ratios (ie, the burden averted per dose) for all 14 included vaccines and diseases, hereafter referred to as full runs. Both runs were modelled from Jan 1, 2000, to Dec 31, 2100. Countries were included if they were in the Gavi, the Vaccine Alliance portfolio; had notable burden; or had notable strategic vaccination activities. These countries represented the majority of global vaccine-preventable disease burden. Vaccine coverage was informed by historical estimates from WHO-UNICEF Estimates of National Immunization Coverage and the immunisation repository of WHO for data up to and including 2021. From 2022 onwards, we estimated coverage on the basis of guidance about campaign frequency, non-linear assumptions about the recovery of routine immunisation to pre-disruption magnitude, and 2030 endpoints informed by the WHO Immunization Agenda 2030 aims and expert consultation. We examined three main scenarios: no disruption, baseline recovery, and baseline recovery and catch-up. FINDINGS: We estimated that disruption to measles, rubella, HPV, hepatitis B, meningitis A, and yellow fever vaccination could lead to 49 119 additional deaths (95% credible interval [CrI] 17 248-134 941) during calendar years 2020-30, largely due to measles. For years of vaccination 2020-30 for all 14 pathogens, disruption could lead to a 2·66% (95% CrI 2·52-2·81) reduction in long-term effect from 37 378 194 deaths averted (34 450 249-40 241 202) to 36 410 559 deaths averted (33 515 397-39 241 799). We estimated that catch-up activities could avert 78·9% (40·4-151·4) of excess deaths between calendar years 2023 and 2030 (ie, 18 900 [7037-60 223] of 25 356 [9859-75 073]). INTERPRETATION: Our results highlight the importance of the timing of catch-up activities, considering estimated burden to improve vaccine coverage in affected cohorts. We estimated that mitigation measures for measles and yellow fever were particularly effective at reducing excess burden in the short term. Additionally, the high long-term effect of HPV vaccine as an important cervical-cancer prevention tool warrants continued immunisation efforts after disruption. FUNDING: The Vaccine Impact Modelling Consortium, funded by Gavi, the Vaccine Alliance and the Bill & Melinda Gates Foundation. TRANSLATIONS: For the Arabic, Chinese, French, Portguese and Spanish translations of the abstract see Supplementary Materials section.

Financing And Funding Gap For 16 Vaccines Across 94 Low- And Middle-Income Countries, 2011-30.

We estimated immunization program costs, financing, and funding gaps for sixteen vaccines among ninety-four low- and middle-income countries during the period 2011-30. Inputs were obtained from the Institute for Health Metrics and Evaluation, the 2020 Decade of Vaccine Economics costing analysis, the World Health Organization, Gavi, and the United Nations Children's Fund. We found a total funding gap of $38.4 billion between 2011 and 2030, with the cost of immunization delivery being the main driver (86 percent) of the funding gap. On average, government financing of vaccination programs steadily rises throughout the period. However, the decline in both Gavi and development assistance for health (DAH) financing anticipated between 2011 and 2030 outpaces the forecasted increases in domestic government immunization spending. Probabilistic sensitivity analysis was applied to both the costing and the scenario analyses to address uncertainty in the financing of vaccines and vaccine delivery. The results highlight a narrowing gap for vaccine acquisition but a growing gap for vaccine delivery, which emphasizes the critical need for resource mobilization and sustainable financial strategies for immunization programs at national and global levels, as well as a need to address the COVID-19 pandemic's potential effects on government financing for vaccines between 2021 and 2030.

Modeling the impact of vaccination for the immunization Agenda 2030: Deaths averted due to vaccination against 14 pathogens in 194 countries from 2021 to 2030.

BACKGROUND: The Immunization Agenda 2030 (IA2030) Impact Goal 1.1. aims to reduce the number of future deaths averted through immunization in the next decade. To estimate the potential impact of the aspirational coverage targets for IA2030, we developed an analytical framework and estimated the number of deaths averted due to an ambitious vaccination coverage scenario from 2021 to 2030 in 194 countries. METHOD: A demographic model was used to determine annual age-specific mortality estimates associated with vaccine coverage rates. For ten pathogens (Hepatitis B virus, Haemophilus influenzae type B, human papillomavirus, Japanese encephalitis, measles, Neisseria meningitidis serogroup A, Streptococcus pneumoniae, rotavirus, rubella, yellow fever), we derived single measures of country-, age-, and pathogen-specific relative risk of deaths conditional upon coverage rates, leveraging the data from 18 modeling groups as part of the Vaccine Impact Model Consortium (VIMC) for 110 countries. We used a logistic regression model to extrapolate the relative risk estimates to countries that were not modeled by VIMC. For four pathogens (diphtheria, tetanus, pertussis and tuberculosis), we used estimates from the Global Burden of Disease 2019 study and existing literature on vaccine efficacy. A future scenario defining years of vaccine introduction and scale-up needed to reach aspirational targets was developed as an input to estimate the long-term impact of vaccination taking place from 2021 to 2030. FINDINGS: Overall, an estimated 51.5 million (95 % CI: 44.0-63.2) deaths are expected to be averted due to vaccinations administered between the years 2021 and 2030. With immunization coverage projected to increase over 2021-2030 an average of 5.2 million per year (4.4-6.3) deaths will be averted annually, with 4.4 million (3.9-5.1) deaths be averted for the year 2021, gradually rising to 5.8 million (4.9-7.5) deaths averted in 2030. The largest proportion of deaths is attributed to Measles and Hepatitis B accounting for 18.8 million (17.8-20.0) and 14.0 million (11.5-16.9) of total deaths averted respectively. INTERPRETATION: The results from this global analysis demonstrate the substantial potential mortality reductions achievable if the IA2030 targets are met by 2030. Deaths caused by vaccine preventable diseases disproportionately affect LMICs in the African region.

Return On Investment From Immunization Against 10 Pathogens In 94 Low- And Middle-Income Countries, 2011-30.

Estimating the value of global investment in immunization programs is critical to helping decision makers plan and mobilize immunization programs and allocate resources required to realize their full benefits. We estimated economic benefits using cost-of-illness and value-of-a-statistical-life approaches and combined this estimation with immunization program costs to derive the return on investment from immunization programs against ten pathogens for ninety-four low- and middle-income countries for the period 2011-30. Using the cost-of-illness approach, return on investment for one dollar invested in immunization against our ten pathogens was 26.1 for the ninety-four countries from 2011 to 2020 and 19.8 from 2021 to 2030. Using the value-of-a-statistical-life approach, return on investment was 51.0 from 2011 to 2020 and 52.2 from 2021 to 2030. The results demonstrate continued high return on investment from immunization programs. The return-on-investment estimates from this study will inform country policy makers and decision makers in funding agencies and will contribute to efforts to mobilize resources for immunization. Realization of the full benefits of immunization will depend on sustained investment in and commitment to immunization programs.

Cost of Nine Pediatric Infectious Illnesses in Low- and Middle-Income Countries: A Systematic Review of Cost-of-Illness Studies.

BACKGROUND: Cost-of-illness data from empirical studies provide insights into the use of healthcare resources including both expenditures and the opportunity cost related to receiving treatment. OBJECTIVE: The objective of this systematic review was to gather cost data and relevant parameters for hepatitis B, pneumonia, meningitis, encephalitis caused by Japanese encephalitis, rubella, yellow fever, measles, influenza, and acute gastroenteritis in children in low- and middle-income countries. DATA SOURCES: Peer-reviewed studies published in public health, medical, and economic journals indexed in PubMed (MEDLINE), Embase, and EconLit. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS: Studies must (1) be peer reviewed, (2) be published in 2000-2016, (3) provide cost data for one of the nine diseases in children aged under 5 years in low- and middle-income countries, and (4) generated from primary data collection. LIMITATIONS: We cannot exclude missing a few articles in our review. Measures were taken to reduce this risk. Several articles published since 2016 are omitted from the systematic review results, these articles are included in the discussion. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: The review yielded 37 articles and 267 sets of cost estimates. We found no cost-of-illness studies with cost estimates for hepatitis B, measles, rubella, or yellow fever from primary data. Most estimates were from countries in Gavi preparatory (28%) and accelerated (28%) transition, followed by those who are initiating self-financing (22%) and those not eligible for Gavi support (19%). Thirteen articles compared household expenses to manage illnesses with income and two articles with other household expenses, such as food, clothing, and rent. An episode of illness represented 1-75% of the household's monthly income or 10-83% of its monthly expenses. Articles that presented both household and government perspectives showed that most often governments incurred greater costs than households, including non-medical and indirect costs, across countries of all income statuses, with a few notable exceptions. Although limited for low- and middle-income country settings, cost estimates generated from primary data collection provided a 'real-world' estimate of the economic burden of vaccine-preventable diseases. Additional information on whether common situations preventing the application of official clinical guidelines (such as medication stock-outs) occurred would help reveal deficiencies in the health system. Improving the availability of cost-of-illness evidence can inform the public policy agenda about healthcare priorities and can help to operationalize the healthcare budget in local health systems to respond adequately to the burden of illness in the community.

The Potential Economic Value of a Zika Vaccine for a Woman of Childbearing Age.

INTRODUCTION: With Zika vaccine candidates under development and women of childbearing age being the primary target population, now is the time to map the vaccine (e.g., efficacy and duration of protection) and vaccination (e.g., cost) characteristic thresholds at which vaccination becomes cost effective, highly cost effective, and cost saving. METHODS: A Markov model was developed (to represent 2019 circumstances, US$ and INT$, Region of the Americas) to simulate a woman of childbearing age and the potential risk and clinical course of a Zika infection. RESULTS: Compared with no vaccination, vaccination was cost effective (incremental cost-effectiveness ratio: US$1,254-$82,900/disability-adjusted life years averted) when the risk of infection was ≥0.05%-0.08% (varying with country income), vaccine efficacy was ≥25%, and vaccination cost was US$1-$7,500 (INT$5-$10,000 depending on country income level). Vaccination was dominant (i.e., saved costs and provided beneficial health effects) when the infection risk was ≥0.1% for a vaccine efficacy ≥75% and when the infection risk was ≥0.5% for a vaccine efficacy ≥25%, for scenarios where vaccination conferred a 1-year duration of protection and cost ≤$200. In some cases, the vaccine was cost effective when the risk was as low as 0.015%, the cost was as high as $7,500 (INT$10,000), the efficacy was as low as 25%, and the duration of protection was 1 year. CONCLUSIONS: The thresholds at which vaccination becomes cost effective and cost saving can provide targets for Zika vaccine development and implementation.