The need and ongoing efforts to understand the full value of improved influenza vaccines

Identification and sizing of the current use cases for seasonal influenza vaccines

INTRODUCTION

Influenza disease continues to have significant global burden. Despite broader use of seasonal influenza vaccines in high resource settings, our understanding of use cases for seasonal influenza vaccines, their relative size, and their relationship to the barriers to adoption in different populations and settings, is limited. This study is a first attempt to identify the use cases for seasonal influenza vaccines to support the design of global influenza vaccination strategies that are better tailored to different implementation contexts and the development of improved influenza vaccines that are more aligned with the different user needs.

METHODS

By applying a design-based user-centric approach, we implemented a process, including a desk review, a survey, and interviews, to define the current use cases for seasonal influenza vaccines.

RESULTS

Nine use cases have been identified as relevant across all different countries and immunization programme designs and validated by experts.

DISCUSSION

The identified use cases of seasonal influenza vaccines can support the optimization of vaccination programmes to increase their public health impact. The use cases identified through this work can help signal to policymakers the most important populations and delivery channels to increase the impact of seasonal influenza vaccination programmes and help estimate programmatic requirements necessary for the supportive policy recommendations. The use cases can also support the design of measures aimed at increasing access in low resource settings and coverage in settings where seasonal vaccines are widely used. The use cases can also help to inform the development, of improved influenza vaccines by highlighting the specific product characteristics relevant to their most impactful uses in different programmatic settings.

Global production capacity of seasonal and pandemic influenza vaccines in 2023

INTRODUCTION

Vaccination is a critical part of the response to an influenza pandemic. Future influenza pandemics will likely leverage existing production processes and manufacturing facilities for seasonal influenza to make pandemic vaccines. Therefore, pandemic influenza vaccine response is heavily dependent on seasonal influenza vaccine production capacity.

METHODS

WHO monitors global vaccine production to inform pandemic preparedness by regularly surveying influenza vaccine manufacturers to estimate both seasonal and potential pandemic vaccine production capacity overall and by region, vaccine type, and manufacturing process. The last survey estimates were for 2019; here, we report updated estimates based on data from the 2023 survey and compare to estimates from previous surveys.

RESULTS

Our analysis estimates that annual seasonal influenza vaccine production capacity has remained relatively stable since 2019 at 1.53 billion doses and pandemic vaccine capacity at 4.13 and 8.26 billion doses for moderate and best case scenarios, respectively. Over 80 % of seasonal and pandemic vaccine production capacity relies on embryonated eggs, and inactivated influenza virus vaccines comprise the majority of vaccine supply. There is influenza vaccine manufacturing capacity in all WHO regions, except for the African Region, though influenza vaccine production is concentrated in high and upper-middle income countries. The ability to achieve maximum production capacity could be hindered by access to eggs and other ancillary supplies.

CONCLUSIONS

While influenza vaccine production capacity has been sustained since 2019, significant gaps persist in its distribution, especially in low and lower-middle income countries, and most notably in the African region. This imbalance in production could result in unequal access to vaccines in the event of a pandemic. Strengthening local vaccine manufacturing, promoting seasonal vaccination programmes, and investing in research and development of next-generation influenza vaccines or improved production platforms are essential to improve pandemic preparedness, sustain the influenza vaccine market, and enable more robust local responses.

Advancing influenza vaccines: A review of next-generation candidates and their potential for global health impact

BACKGROUND

Influenza vaccines are an essential tool for influenza prevention, control and preparedness. However, demand for them and their programmatic suitability globally is significantly influenced by their variable effectiveness against influenza illness annually, limited duration of protection and need for yearly updating and vaccination. As such, the World Health Organization and major funders, such as the United States National Institute of Allergy and Infectious Diseases and Bill and Melinda Gates Foundation, have strongly encouraged developing influenza vaccines with increased efficacy, breadth and duration of protection. Here, we review the next-generation influenza vaccine pipeline, focusing on products in clinical development, and compare their characteristics to currently approved seasonal influenza vaccines.

METHODS

To identify and characterize next-generation influenza vaccine candidates, we conducted a comprehensive literature review, using the CIDRAP Universal Influenza Vaccine Technology Landscape as a primary reference source and extracting additional information from peer-reviewed manuscripts, clinical trial records and other media in the public domain.

RESULTS

Our analysis reveals a robust clinical development pipeline for next-generation influenza vaccines, featuring a diversity of approaches to address existing vaccine challenges and several candidates in advanced stages of development. mRNA vaccines emerged as a predominant platform, as evidenced by the number of candidates focused on improved seasonal protection as well as combination vaccine candidates targeting additional respiratory viruses.

CONCLUSION

While still early in development, results from universal or broadly protective products are promising and warrant continued investment from funders. As most Phase 3 candidates are mRNA-based and include combination vaccines, it is critical to begin considering how these new products may become integrated into the current global influenza vaccine strain selection and manufacturing ecosystems, and existing immunization programmes.

The Full Value of Vaccine Assessments Concept-Current Opportunities and Recommendations

For vaccine development and adoption decisions, the 'Full Value of Vaccine Assessment' (FVVA) framework has been proposed by the WHO to expand the range of evidence available to support the prioritization of candidate vaccines for investment and eventual uptake by low- and middle-income countries. Recent applications of the FVVA framework have already shown benefits. Building on the success of these applications, we see important new opportunities to maximize the future utility of FVVAs to country and global stakeholders and provide a proof-of-concept for analyses in other areas of disease control and prevention. These opportunities include the following: (1) FVVA producers should aim to create evidence that explicitly meets the needs of multiple key FVVA consumers, (2) the WHO and other key stakeholders should develop standardized methodologies for FVVAs, as well as guidance for how different stakeholders can explicitly reflect their values within the FVVA framework, and (3) the WHO should convene experts to further develop and prioritize the research agenda for outcomes and benefits relevant to the FVVA and elucidate methodological approaches and opportunities for standardization not only for less well-established benefits, but also for any relevant research gaps. We encourage FVVA stakeholders to engage with these opportunities.

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.