The World Health Organization said on Monday it was thrashing out a new list of priority pathogens that risk sparking pandemics or outbreaks and should be kept under close observation.
The WHO said the aim was to update a list used to guide global research and development (R&D) and investment, especially in vaccines, tests, and treatments.
As part of that process, which started on Friday, the United Nations' health agency is convening over 300 scientists to consider evidence on more than 25 virus families and bacteria.
They will also consider the so-called "Disease X" – an unknown pathogen that could cause a serious international epidemic.
"Targeting priority pathogens and virus families for research and development of countermeasures is essential for a fast and effective epidemic and pandemic response," said WHO emergencies director Michael Ryan.
"Without significant R&D investments prior to the COVID-19 pandemic, it would not have been possible to have safe and effective vaccines developed in record time."
The list was first published in 2017.
It currently includes COVID-19, Ebola virus disease and Marburg virus disease, Lassa fever, Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS), Nipah, Zika, and Disease X.
For each pathogen identified as a priority, experts will pinpoint knowledge gaps and research priorities.
Desired specifications for vaccines, treatments, and diagnostic tests can then be drawn up.
Efforts are also made to facilitate clinical trials to develop such tools, while efforts to strengthen regulatory and ethics oversight are also considered.
The revised list is expected to be published before April 2023.
The pathogen threat sessions come as the WHO prepares for the next round of talks towards a pandemic treaty.
An intergovernmental negotiating body is paving the way towards a global agreement that could eventually regulate how nations prepare for and respond to future pandemic threats.
They are due to meet in Geneva from December 5 to 7 for a third meeting to draft and negotiate a WHO convention or other kind of international agreement on pandemic preparedness and response.
A progress report will be presented to WHO member states next year, with the final outcome presented for their consideration in 2024.
An initial draft text for the December meeting emerged last week.
The Panel for a Global Public Health Convention, an independent coalition of statespersons and health leaders, said the draft did not go far enough, despite its bright spots.
The panel said Monday that more should be done to establish accountability and clear timelines for alert and response to avoid damaging consequences when an outbreak emerges.
"Once an outbreak is detected, there are often a few critical hours to report, assess and act to stop the spread of a disease before it becomes virtually unstoppable," the panel said in a statement.
"The current draft does not go far enough to call out the urgency needed to either prepare for disease X or known pathogens, or to respond at the early stage," it said.
"From December 2019 when information about the new coronavirus was suppressed, to multiple countries taking a 'wait and see' approach when COVID-19 cases were first reported… we've seen the damaging consequences of inaction at the onset."