Common virus more likely to be next pandemic than Disease X or SARS

Flu is the most likely pathogen to spark the next global pandemic, disease experts have warned. More than half of a worldwide group of infectious diseases experts ranked influenza as the number one pathogen of concern in terms of pandemic potential.

An as-yet unknown disease ominously named Disease X was ranked second in the list of pathogens most likely to spark another pandemic. Other pathogens with a potential to cause a pandemic included the Coronavirus, Ebola, the original SARS virus from the early 2000s and Crimean-Congo haemorrhagic fever (CCHF).

The study, which will be formally presented at the European Society of Clinical Microbiology and Infectious Diseases' (ESCMID) Global Congress in Barcelona later this month, quizzed 187 experts on global infectious diseases from 57 different countries. Each expert was asked to rank various pathogens based on their perceived pandemic risk, encompassing diseases featured in the World Health Organisation's Research and Development Blueprint for Action to Prevent Epidemics, which focuses on key infectious diseases that pose significant threats to public health.

Experts ranked the pathogens in the order of their perceived risk, and also suggested pathogens not listed to include in their maximum of 14. The experts' responses showed influenza viruses were viewed as the pathogen of highest concern, with over half (57 per cent) ranking it first and around a sixth (17 per cent) ranking it second.

More than a fifth (21 per cent) of the experts ranked the as-yet-unknown Disease X as having the highest pandemic potential, with another 14 per cent ranking it second. The Coronavirus, or SARS-CoV-2, came third with nearly one in ten (8 per cent) ranking it first and 16 per cent ranking it second, whilst the original SARS-CoV virus that circulated in 2002-03 was voted number one by two per cent of respondents and second by eight per cent.

The CCHF and Ebola viruses were joint fifth, with 1.6 per cent of experts voting them first. Nipah virus, henipavirus, and Rift Valley fever virus were among the pathogens ranked lowest in terms of their perceived pandemic potential.

Dr Jon Salmanton-García, the lead author of the study from the University of Cologne in Germany, explained: "The study revealed that influenza, Disease X, SARS-CoV-2, SARS-CoV, and the Ebola virus are the most worrisome pathogens concerning their pandemic potential.

"These pathogens are characterised by their transmissibility through respiratory droplets and a history of previous epidemic or pandemic outbreaks.”

On influenza receiving the top ranking, Dr Salmanton-García said the flu already causes 'mini pandemics' across the world each winter. "Each winter we have an influenza season," he said.

"One could say that this means that every winter there are little pandemics. They are more or less controlled because the different strains are not virulent enough.

"Yet, every season the strains involved change, that is the reason why we can get influenza several times in life and vaccines change year to year. In case a new strain becomes more virulent, this control could be lost.”

However, Dr Salmanton-García added that the world is now much more prepared for a global pandemic after Covid. In the COVID-19 pandemic, we have learned many things on how to approach a respiratory virus pandemic," he continued.

"This includes social distancing, hand cleaning, face masks, a renewed focus on vaccination, and trust in healthcare institutions. In parallel, institutions have also learnt a lot. Preparedness and surveillance are now, vitally, better-funded.”

The study was published in the journal Travel Medicine and Infectious Disease.