Nipah virus: a priority pathogen
Nipah virus was identified by WHO in 2017 as a priority pathogen under the Research and Development (R&D) Blueprint because of its high public health importance and the urgent need to accelerate the development of medical countermeasures (MCMs). Recognising the growing threat posed by the virus and its emergence in countries of the WHO South-East Asia Region, WHO South-East Asia Regional Office (SEARO) designated Nipah virus as a regional priority pathogen in 2018.
To strengthen regional preparedness and response, WHO subsequently developed the South-East Asia Regional Strategy for the Prevention and Control of Nipah Virus Infection 2023–2030, which provides a comprehensive framework for prevention, preparedness, detection, response, and resilience against Nipah virus infection across the Region.
Addressing a critical evidence gap
Although Nipah virus infection continues to be associated with high case fatality ratios, the ability to accurately predict which patients are at greatest risk of severe disease and poor outcomes remains limited. Standardised and validated disease severity scores could help address this challenge.
Recognising the importance of developing a standardised Nipah disease severity score (DSS), a critical tool for outbreak response, clinical research, and vaccine evaluation, WHO SEARO collaborated with the Coalition for Epidemic Preparedness Innovations (CEPI) and PATH to convene a stakeholder consultation under the CEPI’s Nipah Vaccine Outbreak Trial Planning and Preparedness (NiVOTriPP) Project.
WHO, CEPI and PATH convened a stakeholder consultation in Kathmandu, Nepal, from 11 to 13 August to advance the development of a Nipah disease severity score. (Photo credit: CEPI)
The NiVOTriPP project was initiated to develop a scenario-specific, flexible, and adaptive clinical trial protocol for evaluation of Nipah vaccine efficacy (VE) in case of a potentially large outbreak (i.e., Nipah-X). While the current epidemiology of Nipah virus disease makes it practically infeasible to evaluate VE, any change in epidemiology leading to larger outbreaks may allow conduct of such trials. NiVOTriPP is set up to prepare for such a potential scenario.
The DSS is being developed in parallel with the protocol under NiVOTriPP, and its primary purpose is to support vaccine evaluation in clinical trials by enabling the standardised and consistent measurement of disease severity during Nipah virus outbreaks.
The consultation also responded to calls for strengthening public-private partnerships in the development of medical countermeasures and for promoting research collaboration as outlined in the implementation framework of the WHO South-East Asia Regional Strategy for the Prevention and Control of Nipah Virus Infection 2023–2030.
Bringing together multidisciplinary expertise
The consultation brought together international and regional experts in Nipah virus surveillance, outbreak response, vaccine trial design in outbreak settings, clinical management, biostatistics and disease severity score development.
The primary objective of the consultation was to obtain expert input on the factors to be included in the scoring system and the methodological approaches for possible derivation, refinement, and validation.
During the three-day meeting, participants reviewed the available evidence and identified the most relevant clinical signs, symptoms, and other factors for inclusion in the DSS. Experts also reviewed methodological approaches for score development, refinement, and validation.
The consultation brought together multidisciplinary experts from across the WHO South-East Asia Region and beyond. (Photo credit: CEPI)
Next steps
An initial draft DSS was developed based on the discussions and consensus reached during the consultation. Further review and refinement will be undertaken through a series of technical working group activities during the next phase of the project.
WHO SEARO, CEPI, and PATH will continue to partner on refining and validating the draft DSS. In addition to its primary intended use as a standardised, evidence-based tool for estimating vaccine efficacy in forthcoming studies, the DSS has the potential to support therapeutic research and improve clinical management of Nipah virus disease across the region.