UKHSA warning as 'priority pathogen' watch list reveals 24 'danger' viruses (2025)

Bird flu and coronaviruses are diseases in the 'deadly' virus families that health officials warn have pandemic potential

Health bosses have revealed the most dangerous viruses and diseases that pose the biggest threat to public health – and could even have pandemic potential.

The UK Health Security Agency (UKHSA) has revealed its priority pathogen watch list to identify which diseases pose the most danger to Brits and to inform scientists and investors when developing treatments and vaccines.

The UKHSA has given a risk rating of high, moderate, or low pandemic potential for 24 pathogens. Some are viruses with global pandemic potential, like Covid or bird flu, and others are emerging viruses with no existing treatments.

Scientists say the list highlights the importance of being as prepared as possible for "Disease X", the name given by the World Health Organization (WHO) to an unknown future pathogen with serious epidemic or pandemic potential.

Dr Isabel Oliver, Chief Scientific Officer for UKHSA, said: "This tool is a vital guide for industry and academia, highlighting where scientific research can be targeted to boost UK preparedness against health threats.

"We are using the tool as part of our conversations with the scientific community, to help ensure that investment is focused to where it can have the biggest impact.

"We hope this will help to speed up vaccine and diagnostics development where it is most needed, to ensure we are fully prepared in our fight against potentially deadly pathogens."

This rating does not rank the pathogens nor highlight which the UKHSA considers most likely to cause the next pandemic. However, the list reveals four virus families found to have high pandemic risk:

• The Paramyxoviridae family which includes measles and the Nipah virus
• The Picornaviridae family which causes enteroviruses that trigger polio-like diseases
• The Coronaviridae family which includes coronaviruses such as Covid-19 and Mers
• The Orthomyxoviridae family which causes forms of influenza, including bird flu

'A threat far worse than Covid' and 'impossible to control'

A leading scientist has warned that one virus on the list poses a “threat far worse than Covid."

Prof Mark Woolhouse, Professor of Infectious Disease Epidemiology, and Director of the Tackling Infections to Benefit Africa at the University of Edinburgh, said: “The UKHSA are also right to be concerned about another family of viruses, the Paramyxoviridae. This is a group that includes the measles virus, itself a continuing cause for concern with large outbreaks regularly reported from around the world."

According to Prof Woolhouse, a measles-like virus would have a much higher R number than original Covid variants, meaning one infected person would spread the virus to more people. He says this would make the virus more deadly and "impossible to control by even the strictest lockdown."

“This is the kind of pandemic that public health agencies around the world are most concerned about," Prof Woolhouse added.

However, he also warns that the health leaders in the UK should not "put all our eggs in one basket" as "Disease X" could come from unexpected threats.

"The possibility of different kinds of threat – different transmission routes, different types of disease, different populations at risk – means that our response needs to be scalable, adaptable and quick," Prof Woolhouse warned.

'Disease X'

One scientist even warns the list could do more harm than good, potentially putting public health at a higher risk of a pandemic threat.

Prof Robert Read, Professor of Infectious Diseases, University of Southampton, and Editor in Chief, Journal of Infection, said: "Unfortunately, pathogens emerge or change constantly, and it is difficult to predict big infectious disease problems coming down the line. For this reason, I think this list is at best pointless, and at worst potentially harmful to public health."

"Pointless because the list of viruses is so long that it's tricky to name a significant viral pathogen that has not been included. Potentially harmful because a prescriptive list like this could misdirect funding towards certain infections, and away from problems that need urgently to be solved."

However, others have welcomed the UKHSA list. According to Prof Emma Thomson, Director of the MRC-University of Glasgow Centre for Virus Research, the list is a "valuable" resource that will "improve preparedness for future infectious disease threats in the UK."

She also warns that it is important to keep "Disease X" at the forefront of pathogen research. "There are an estimated 320,000 undiscovered viruses in wildlife that could have spillover potential," Prof Thomson said.

"Enhanced technologies for virus discovery and characterisation—such as unbiased metagenomic sequencing and improved surveillance—will be essential to ensure that novel pathogens are rapidly identified and assessed for pandemic potential."

Full list of dangerous diseases or pathogens

• Adenovirus
• Lassa fever
• Norovirus
• Middle East respiratory syndrome (Mers)
• Ebola
• Flaviviridae (which includes dengue, Zika and hepatitis C)
• Hantavirus
• Crimean-Congo haemorrhagic fever
• Flu (non-seasonal, including bird flu)
• Nipah virus
• Oropouche
• Rift Valley fever
• Acute flaccid myelitis
• Human metapneumovirus (HMPV)
• Mpox
• Chikungunya
• Anthrax
• Q fever
• Enterobacteriaceae (such as E. coli)
• Tularaemia
• Moraxellaceae
• Gonorrhoea
• Staphylococcus