Writing in The Conversation, University of Edinburgh epidemiologist Mark Woolhouse describes a newly published catalogue that ranks RNA viruses by their potential to spark a public health emergency. Given that scientists discover two or three previously unseen human viruses in a typical year, and that past discoveries such as HIV-1 and Sars-CoV-2 went on to kill tens of millions, the catalogue aims to help researchers quickly judge whether a newly found pathogen could become the next pandemic threat.

Of the thousands of known RNA virus species, only 239 infect humans, and for two-thirds of these an infected person is highly unlikely to pass the infection on, as they are zoonotic viruses caught from animals, such as rabies. The greater danger comes from the few dozen "outbreak" viruses already able to spread between people, including Zaire ebolavirus, Chikungunya, Zika, Oropouche and mpox, all of which have since caused major epidemics. Woolhouse notes that his team's 2019 work accurately predicted the profile of a "disease X" pandemic virus — closely related to human-spreading viruses but emerging separately from animals — which matched Sars-CoV-2 exactly, and warns that a novel measles-like virus could prove far worse than COVID. He stresses that Andes and Bundibugyo viruses, like COVID, spread undetected for weeks, so faster identification of new viruses could deny the next pandemic its head start.