The risk of epidemics or pandemics caused by emerging or re-emerging pathogens remains a constant global threat. The COVID-19 pandemic1,2, as well as recurrent outbreaks of Ebola, Marburg, mpox, and other viruses are stark reminders of this. When outbreaks occur, understanding the origins of the pathogens and their pathways into the human population is critical. This knowledge not only guides the immediate public health response by identifying at-risk populations and transmission dynamics, it also informs epidemic and pandemic preparedness efforts, reducing the likelihood of future re-emergence.

The need to understand the origins of novel pathogens

In November 2021, the World Health Organization (WHO) appointed 27 scientists with a diverse range of appropriate expertise (acting in an individual capacity) to advise the Organization on technical and scientific considerations regarding the origins of emerging and re-emerging pathogens. This Scientific Advisory Group for the Origins of Novel Pathogens (SAGO)3 was tasked to develop a standardized framework to assist member states in investigating the origins of emerging and re-emerging infectious pathogens as soon as they are identified. This will support national responses in quickly identifying pathogens, implementing measures to contain the spread, where possible, and ensuring all relevant data is captured when investigating the origins. The framework encourages rapid reporting to national and international public health agencies (including WHO) and to the global community of scientific experts to allow for an effective global response. Such a comprehensive guide has not been available so far and aims to improve the investigation process of the emergence of future pathogens. The SAGO has continuously advocated for a transparent, comprehensive, and coordinated approach to investigations and research on novel pathogens and has advised on studies into the origins of SARS-CoV-2 and monkeypox virus4. With the support of the SAGO, WHO has launched this global framework to define and guide studies into the origins of emerging and re-emerging pathogens with epidemic and pandemic potential5, the components of which are described here.

About the framework

The framework proposes a multi-disciplinary, multi-stakeholder, One Health approach to ensure coordination and collaboration in better understanding the origins of a pathogen’s initial emergence or re-emergence through a set of scientific investigations and research studies. The global framework outlines six key technical elements (Table 1) needed as part of the investigation and provides practical guidance on the required capacities and on specific recommended studies. The elements are complementary and should be conducted concurrently, depending on the circumstances of the emergence, as soon as a novel or re-emerging pathogen is detected.

Table 1 Six key elements to include in investigations of the origins of novel pathogens presented in the global framework
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The framework highlights the capacities required at a country level to effectively implement the six elements and advocates for capacity building in these areas, including surveillance systems and expertise required to detect zoonotic events, which account for the majority of novel pathogen emergence. Advice related to biosafety/biosecurity investigations was also developed in consultation with WHO’s Technical Advisory Group on Biosafety6. The framework provides recommendations on laboratory biosafety and biosecurity measures that should be in place in countries and on the scientific tools required to investigate if a pathogen is of either zoonotic origin or linked to possible laboratory-related events.

The framework recommends that these scientific investigations into the origins of a novel pathogen are implemented as soon as possible from the time the pathogen is detected and verified. It is imperative for countries to act swiftly to implement the framework, allowing multidisciplinary teams to investigate early cases and possible spillover events from zoonotic exposures. The framework further guides countries on the necessary surveillance systems that should be in place to identify the pathogen in humans, animals, and the environment, on laboratory capacities needed to detect and characterize pathogens as well as genomic investigations required to identify the closest precursor strains that can identify reservoir or intermediate hosts. The framework promotes a One Health approach to detect and respond to emerging and zoonotic diseases and is in line with International Health Regulations’ core capacities (Fig. 1). Transparent investigations into the origins of novel pathogens require close cooperation between the local government, scientists, and international agencies.

Fig. 1: Implementing the WHO global framework to define and guide studies into the origins of novel pathogens.
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The six key elements of the framework are indicated relative to the capacities countries need to have in place and their alignment with the International Health Regulations (IHR), emphasizing the importance of the One Health approach.

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Conclusion

SARS-CoV-2 was not the first novel pathogen to trigger a pandemic and it will not be the last. Identifying how these pathogens emerge is both a scientific imperative, to help prevent future epidemics and pandemics, and a moral imperative for the sake of those who have lost their lives to COVID-19 and other epidemics and pandemics. This framework is a tool for meeting those twin imperatives, towards making the world a safer place.