UK vaccines network: Mapping priority pathogens of epidemic potential and vaccine pipeline developments

Preparing the developing world for the next pandemic: Evidence from China's R&D blueprint for emerging infectious diseases

BACKGROUND

With double pressures of endemic and imported emerging infectious diseases (EIDs), China's ability to detect, prevent and control the unknown virus is of regional and global interest. This study aimed to establish an R&D Blueprint for EIDs in China by identifying the list of prioritized diseases and medical countermeasures (MCMs) that need proactive actions for the next pandemic.

METHODS

The process mainly referred to the World Health Organization's prioritization methodology, supplemented by pipeline landscape, rapid risk assessment and multi-dimensional analysis. The study included five steps: 1) identifying potential pathogens, 2) screening into the long list, 3) prioritizing the long list, 4) identifying the final list and 5) generating an R&D Blueprint.

RESULTS

China's R&D Blueprint identified 14 viral pathogens and two virus groups (i.e., Influenza HxNy and Coronavirus X) for proactive and representative MCM development. At least one diagnostic candidate in preclinical study, and one therapeutic and one vaccine candidate in Phase I/II clinical trials for each prioritized pathogen were suggested to be developed as strategic national stockpiles. Various generalized and innovative platform technologies were also highlighted for enhancing overall capacities of EID preparedness and response, covering basic research, experiment, detection, prevention and control, surveillance and information sharing.

CONCLUSIONS

This is the first study in developing countries that established an R&D Blueprint of prioritized diseases, countermeasures and technologies. Our findings could help to drive pre-emptive scientific and technological actions toward emerging pathogens that may cause the next epidemic and could provide evidence-based strategies for developing countries to establish their national health research agenda tailored to health and research context under resource-limited settings.

Serological evidence of zoonotic filovirus exposure among bushmeat hunters in Guinea

Human Ebola virus (EBOV) outbreaks caused by persistent EBOV infection raises questions on the role of zoonotic spillover in filovirus epidemiology. To characterise filovirus zoonotic exposure, we collected cross-sectional serum samples from bushmeat hunters (n = 498) in Macenta Prefecture Guinea, adjacent to the index site of the 2013 EBOV-Makona spillover event. We identified distinct immune signatures (20/498, 4.0%) to multiple EBOV antigens (GP, NP, VP40) using stepwise ELISA and Western blot analysis and, live EBOV neutralisation (5/20; 25%). Using comparative serological data from PCR-confirmed survivors of the 2013-2016 EBOV outbreak, we demonstrated that most signatures (15/20) were not plausibly explained by prior EBOV-Makona exposure. Subsequent data-driven modelling of EBOV immunological outcomes to remote-sensing environmental data also revealed consistent associations with intact closed canopy forest. Together our findings suggest exposure to other closely related filoviruses prior to the 2013-2016 West Africa epidemic and highlight future surveillance priorities.

Current progress towards prevention of Nipah and Hendra disease in humans: A scoping review of vaccine and monoclonal antibody candidates being evaluated in clinical trials

OBJECTIVES

Nipah and Hendra are deadly zoonotic diseases with pandemic potential. To date, no human vaccine or monoclonal antibody (mAb) has been licensed to prevent disease caused by these pathogens. The aim of this scoping review was to identify and describe all Phase I, II, and III clinical trials of vaccine candidates or mAbs candidates designed to prevent Nipah and Hendra in humans and to compare the characteristics of the vaccine candidates to characteristics outlined in the Target Product Profile drafted by the World Health Organisation as part of the WHO Research & Development Blueprint for Action to Prevent Epidemics.

METHODS

We searched 23 clinical trial registries, the Cochrane Central Register of Clinical Trials, and grey literature up to June 2023 to identify vaccine and mAb candidates being evaluated in registered clinical trials. Vaccine candidate and trial characteristics were double-extracted for evaluation and the vaccine candidate characteristics were compared with the preferred and critical criteria of the World Health Organisation's Target Product Profile for Nipah virus vaccine.

RESULTS

Three vaccine candidates (Hendra Virus Soluble Glycoprotein Vaccine [HeV-sG-V], PHV02, and mRNA-1215) and one mAb (m102.4) had a registered human clinical trial by June 2023. All trials were phase 1, dose-ranging trials taking place in the United States of America or Australia and enrolling healthy adults. Although all vaccine candidates meet the dose regimen and route of administration criteria of the Target Product Profile, other criteria such as measures of efficacy and reactogenicity will need to be evaluated in the future as evidence becomes available.

CONCLUSION

Multiple vaccine candidates and one mAb candidate have reached the stage of human clinical trials and are reviewed here. Monitoring progress during evaluation of these candidates and candidates entering clinical trials in the future can help highlight many of the challenges that remain.

Scoping review protocol on research prioritisation for preparedness and response to outbreaks of high consequence pathogens

Background

Prioritisation of research activities for infectious disease pathogens is usually undertaken through the identification of important research and knowledge gaps. Research prioritisation is an essential element of both effective responses to disease outbreaks and adequate preparedness. There is however currently no published mapping of activities on and evidence from research prioritisation for high consequence pathogens. The objectives of this review are to map all published research prioritisation exercises on high-consequence pathogens; provide an overview of methodologies employed for prioritising research for these pathogens; describe monitoring and evaluation processes for research areas prioritised; and identify any standards and guidance for effectively undertaking research prioritisation activities for high consequence pathogens.

Methods

The Joanna Briggs Institute guidance of scoping review conduct will be used. The search will be undertaken using the key terms of "research prioritisation", "response", "control", and related terms, and a list of high-consequence pathogens derived from WHO (2020), EMERGE (2019), Europe CDC (2022) and the Association of Southeast Asian Nations (2021). We will search WHO Global Index Medicus; Ovid Medline; Ovid Embase; Ovid Global Health; and Scopus. Backward citations review of the included full text documents will also be conducted. Google Scholar and Overton will be searched for grey literature. Two independent reviewers will screen the retrieved documents using Rayyan and extract data in a data extraction template in Microsoft Excel 2021. Screening results will be presented using the PRISMA-ScR template with narrative synthesis undertaken for the extracted data.

Conclusion

This review will map existing research priorities for high consequence pathogens. Further, it will provide an understanding of methodologies used for prioritisation, processes for monitoring and evaluation of progress made against research agendas, and evidence on standards that could be recommended for effective prioritisation of research for high consequence pathogens.

Lassa fever vaccine use cases and demand: Perspectives from select West African experts

Lassa fever (LF) is a zoonotic viral hemorrhagic disease endemic to several West African countries. Approximately 300-500,000 cases occur annually across all ages with 10-20% case fatality rates. A LF vaccine is a recognized public health priority, with several candidates entering clinical trials. However, the perspectives of regional experts regarding critical vaccine properties, ideal delivery methods, and priority target populations remain unclear. Using a mixed methods approach with a standardized questionnaire, we individually interviewed 8 West African stakeholders, each with extensive knowledge and experience of LF. They strongly favored the use of a mass, proactive campaign strategy to immunize a wide age range of people in high-risk areas, including pregnant women and health care workers. We estimated that these and other plausible delivery scenarios could result in an initial demand of anywhere from 1 to 100 million doses, with most demand coming from Nigeria. These findings may help inform LF vaccine development and deployment efforts.

Establishment of a Nipah Virus Disease Model in Hamsters, including a Comparison of Intranasal and Intraperitoneal Routes of Challenge

Nipah virus (NiV) is an emerging pathogen that can cause severe respiratory illness and encephalitis in humans. The main reservoir is fruit bats, distributed across a large geographical area that includes Australia, Southeast Asia, and Africa. Incursion into humans is widely reported through exposure of infected pigs, ingestion of contaminated food, or through contact with an infected person. With no approved treatments or vaccines, NiV poses a threat to human public health and has epidemic potential. To aid with the assessment of emerging interventions being developed, an expansion of preclinical testing capability is required. Given variations in the model parameters observed in different sites during establishment, optimisation of challenge routes and doses is required. Upon evaluating the hamster model, an intranasal route of challenge was compared with intraperitoneal delivery, demonstrating a more rapid dissemination to wider tissues in the latter. A dose effect was observed between those causing respiratory illness and those resulting in neurological disease. The data demonstrate the successful establishment of the hamster model of NiV disease for subsequent use in the evaluation of vaccines and antivirals.

VelcroVax: a "Bolt-On" Vaccine Platform for Glycoprotein Display

Having varied approaches to the design and manufacture of vaccines is critical in being able to respond to worldwide needs and newly emerging pathogens. Virus-like particles (VLPs) form the basis of two of the most successful licensed vaccines (against hepatitis B virus [HBV] and human papillomavirus). They are produced by recombinant expression of viral structural proteins, which assemble into immunogenic nanoparticles. VLPs can be modified to present unrelated antigens, and here we describe a universal "bolt-on" platform (termed VelcroVax) where the capturing VLP and the target antigen are produced separately. We utilize a modified HBV core (HBcAg) VLP with surface expression of a high-affinity binding sequence (Affimer) directed against a SUMO tag and use this to capture SUMO-tagged gp1 glycoprotein from the arenavirus Junín virus (JUNV). Using this model system, we have solved the first high-resolution structures of VelcroVax VLPs and shown that the VelcroVax-JUNV gp1 complex induces superior humoral immune responses compared to the noncomplexed viral protein. We propose that this system could be modified to present a range of antigens and therefore form the foundation of future rapid-response vaccination strategies. IMPORTANCE The hepatitis B core protein (HBc) forms noninfectious virus-like particles, which can be modified to present a capturing molecule, allowing suitably tagged antigens to be bound on their surface. This system can be adapted and provides the foundation for a universal "bolt-on" vaccine platform (termed VelcroVax) that can be easily and rapidly modified to generate nanoparticle vaccine candidates.

Generalized Modules for Membrane Antigens (GMMA), an outer membrane vesicle-based vaccine platform, for efficient viral antigen delivery

Vaccine platforms enable fast development, testing, and manufacture of more affordable vaccines. Here, we evaluated Generalized Modules for Membrane Antigens (GMMA), outer membrane vesicles (OMVs) generated by genetically modified Gram-negative bacteria, as a vaccine platform for viral pathogens. Influenza A virus hemagglutinin (HA), either physically mixed with GMMA (HA+STmGMMA mix), or covalently linked to GMMA surface (HA-STmGMMA conjugate), significantly increased antigen-specific humoral and cellular responses, with HA-STmGMMA conjugate inducing further enhancement than HA+STmGMMA mix. HA-STmGMMA conjugate protected mice from lethal challenge. The versatility for this platform was confirmed by conjugation of rabies glycoprotein (RABVG) onto GMMA through the same method. RABVG+STmGMMA mix and RABVG-STmGMMA conjugate exhibited similar humoral and cellular response patterns and protection efficacy as the HA formulations, indicating relatively consistent responses for different vaccines based on the GMMA platform. Comparing to soluble protein, GMMA was more efficiently taken up in vivo and exhibited a B-cell preferential uptake in the draining lymph nodes (LNs). Together, GMMA enhances immunity against viral antigens, and the platform works well with different antigens while retaining similar immunomodulatory patterns. The findings of our study imply the great potential of GMMA-based vaccine platform also against viral infectious diseases.

An updated review and current challenges of Guanarito virus infection, Venezuelan hemorrhagic fever

Guanarito virus (GTOV) is a member of the family Arenaviridae and has been designated a category A bioterrorism agent by the US Centers for Disease Control and Prevention. It is endemic to Venezuela's western region, and it is the etiological agent of "Venezuelan hemorrhagic fever" (VHF). Similar to other arenaviral hemorrhagic fevers, VHF is characterized by fever, mild hemorrhagic signs, nonspecific symptoms, thrombocytopenia, and leukopenia. Patients with severe disease usually develop signs of internal bleeding. Due to the absence of reference laboratories that can handle GTOV in endemic areas, diagnosis is primarily clinical and epidemiological. No antiviral therapies are available; thus, treatment includes only supportive analgesia and fluids. GTOV is transmitted by contact with the excreta of its rodent reservoir, Zygodontomys brevicauda. The main reasons for the emergence of the disease may be the increase in the human population, migration, and changes in land use patterns in rural areas. Social and environmental changes could make VHF an important cause of underdiagnosed acute febrile illnesses in regions near the endemic areas. Although there is evidence that GTOV circulates among rodents in different Venezuelan states, VHF cases have only been reported in the states of Portuguesa and Barinas. However, due to the increased frequency of invasions by humans into wildlife habitats, it is probable that VHF could become a public health problem in the nearby regions of Colombia and Brazil. The current Venezuelan political crisis is causing an increase in the migration of people and livestock, representing a risk for the redistribution and re-emergence of infectious diseases.

Access and benefit-sharing by the European Virus Archive in response to COVID-19

Biobanking infrastructures, which are crucial for responding early to new viral outbreaks, share pathogen genetic resources in an affordable, safe, and impartial manner and can provide expertise to address access and benefit-sharing issues. The European Virus Archive has had a crucial role in the global response to the COVID-19 pandemic by distributing EU-subsidised (free of charge) viral resources to users worldwide, providing non-monetary benefit sharing, implementing access and benefit-sharing compliance, and raising access and benefit-sharing awareness among members and users. All currently available SARS-CoV-2 material in the European Virus Archive catalogue, including variants of concern, are not access and benefit-sharing cases per se, but multilateral benefit-sharing has nevertheless occurred. We propose and discuss how a multilateral system enabling access and benefit-sharing from pathogen genetic resources, based on the European Virus Archive operational model, could help bridge the discrepancies between the current bilateral legal framework for pathogen genetic resources and actual pandemic response practices.

Future developments in the prevention, diagnosis and treatment of COVID-19

The impact of the coronavirus disease-2019 (COVID-19) pandemic has been profound and global. Mitigating future waves and overcoming the pandemic is a global public health priority. This review focuses on future developments in the prevention, diagnosis and treatment of COVID-19, which may help to address these challenges. The specific relevance to women's and maternal health, which address the vulnerabilities in this group, is considered. The remarkable scientific achievements that have been made with respect to the development and implementation of both vaccines and therapeutics for COVID-19 are highlighted. The speed and processes for the development, approval and implementation of interventions herald a new way forward in combating emerging infectious diseases. However, it is important to note that this is a rapidly changing field with a constantly evolving knowledge base.

Construction of generic roadmaps for the strategic coordination of global research into infectious diseases of animals and zoonoses

The Strategic Alliance for Research into Infectious Diseases of Animals and Zoonoses (STAR-IDAZ) International Research Consortium (IRC) coordinates global animal health research to accelerate delivery of disease control tools and strategies. With this vision, STAR-IDAZ IRC has constructed four generic research roadmaps for the development of candidate vaccines, diagnostic tests, therapeutics and control strategies for animal diseases. The roadmaps for vaccines, diagnostic tests and therapeutics lead towards a desired target product profile (TPP). These interactive roadmaps describe the building blocks and for each the key research questions, dependencies, challenges and possible solution routes to identify the basic research needed for translation to the TPP. The control strategies roadmap encompasses the vaccine, diagnostic tests, and therapeutic roadmaps within a wider framework focusing on the inter-dependence of multiple tools and knowledge to control diseases for the benefit of animal and human health. The roadmaps are now being completed for specific diseases and complemented by state-of-the-art information on relevant projects and publications to ensure that the necessary research gaps are addressed for selected priority diseases.

A Veterinary Vaccine Development Process Map to assist in the development of new vaccines

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Process Flow Charts providing guidance on how to develop and licence a new veterinary vaccine.

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The importance of producing a clear Target Product Profile (TPP) for a new veterinary vaccine.

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What is required in order to move a new vaccine project from discovery through to development.

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The differences between the human and veterinary vaccine development processes.

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The commercial vaccine regulatory process leading to a marketing authorisation for a new product.

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Identification of potential bottlenecks to the rapid development of a new veterinary vaccine.

The UK Government recognised the importance of vaccines in the control of new emerging disease threats and in 2015 established the UK Vaccine Network to focus on specific areas of need. One of these was the understanding of what is involved in the development of a new vaccine and what are the potential bottlenecks to a rapid response in the face of an epidemic such as Ebola, MERS and more recently COVID-19. A Working Group was established to initially produce a Vaccine Development Process Map for a Human Vaccine. However, in view of the importance of animal wellbeing and the significant impact of diseases with Zoonotic potential, a similar Map has been created outlining the Veterinary Vaccine Development Process. This paper describes the production of that Map and covers the process from the generation of a Target Product Profile (TPP) through Discovery and Feasibility, and on to Product Development and Registration.