The World Health Organization (WHO) has recently updated its list of priority pathogens, identifying over 30 potential threats that could spark the next global pandemic. This comprehensive list now includes the influenza A virus, dengue virus, and monkeypox virus, among others. The aim is to guide research and development efforts in creating effective treatments, vaccines, and diagnostic tools.
The list of priority pathogens is not just a collection of names; it represents a critical roadmap for global health preparedness. One of the key contributors to this effort, an immunologist from Sri Lanka, highlighted the significance of this initiative. The immunologist specialises in the Flaviviridae family of viruses, which includes the virus responsible for dengue fever. The updated list, published on 30 July, was compiled based on the potential of these pathogens to cause widespread public health emergencies. Factors such as high transmissibility, virulence, and limited access to existing vaccines and treatments were considered in the selection process.
The WHO’s previous efforts in 2017 and 2018 identified roughly a dozen priority pathogens. This latest update marks a significant expansion. According to an expert leading the WHO’s R&D Blueprint for Epidemics team, the prioritisation process is essential for identifying critical knowledge gaps that need urgent attention. It ensures that resources are used efficiently and effectively.
Regularly revisiting these lists is crucial. Major global changes such as climate change, deforestation, urbanisation, and international travel all contribute to the evolving landscape of disease risk. The latest effort has broadened its scope by identifying risky pathogens across entire families of viruses and bacteria.
Among the more than 30 priority pathogens now identified are groups like Sarbecovirus, which includes SARS-CoV-2—the virus responsible for the COVID-19 pandemic—and Merbecovirus, which includes the virus causing Middle East respiratory syndrome (MERS). Previous lists included specific viruses causing severe acute respiratory syndrome (SARS) and MERS but did not encompass the entire subgenuses they belong to.
The monkeypox virus has also been added to the list. This virus caused a global outbreak in 2022 and continues to spread in pockets of Central Africa. It is now considered a priority pathogen along with its relative, the variola virus, which causes smallpox. Despite smallpox being eradicated in 1980, the lack of routine vaccination has left many people vulnerable. An unplanned release of the variola virus could have catastrophic consequences. Experts warn that it could potentially be used as a biological weapon by terrorists.
Influenza A viruses are another significant addition to the list. Half a dozen subtypes, including H5, which has recently sparked an outbreak in cattle in the United States, are now considered priority pathogens. Among the newly added bacteria are strains causing cholera, plague, dysentery, diarrhoea, and pneumonia.
Two rodent viruses have also made it onto the list due to their ability to jump to humans with sporadic human-to-human transmission. Climate change and increased urbanisation could elevate the risk of these viruses infecting people. The bat-borne Nipah virus remains on the list because it is deadly and highly transmissible in animals. Currently, there are no therapies available to protect against it.
Many of these priority pathogens are currently confined to specific regions but have the potential for global spread. A virologist at a leading UK research institute emphasised that there isn’t one particular place that is more at risk than others.
In addition to identifying priority pathogens, researchers have created a separate list of ‘prototype pathogens.’ These could serve as model species for basic science studies and the development of therapies and vaccines. This approach may encourage more research into less-studied viruses and bacteria.
Before the COVID-19 pandemic, there were no available human vaccines for any coronaviruses. Developing vaccines for one member of a viral family can instil confidence in the scientific community that it is better equipped to handle major public health emergencies involving related viruses. This concept extends to treatments as well; many antivirals work across a whole group of viruses.
The list of pathogens is based on current knowledge about these viruses. However, some pathogens from the list may never cause an epidemic, and an unforeseen pathogen could emerge as a significant threat in the future. History has shown that predicting the next emerging pathogen is incredibly challenging.
This initiative by the WHO is a vital step in global health preparedness. It serves as a guide for focusing efforts on preventing potential pandemics. The hope is that by identifying these threats early and directing resources towards them, we can mitigate their impact and possibly prevent future global health crises.
The updated list of priority pathogens underscores the importance of vigilance and preparedness in public health. By staying informed and proactive, we can better protect ourselves and future generations from emerging infectious diseases.
