University of Edinburgh catalog ranks viruses by pandemic threat

A list that tries to rank the world’s viruses by pandemic risk has been compiled by researchers at the University of Edinburgh, according to Ars Technica. The catalog focuses on a simple filter that often gets lost in “disease X” talk: whether a virus can spread efficiently between people.

In most years, scientists identify only a handful of viruses never previously seen in humans, and that pace has been broadly steady since the 1960s, the article notes. Most of those discoveries fade into obscure medical literature, but a small number—HIV-1 in 1983 and SARS‑CoV‑2 in 2020—have rewritten public health and public finances for decades. The Edinburgh team’s approach is to treat viral emergence as a recurring, trackable process and to use historical patterns to decide where surveillance and lab work should be concentrated.

The catalog leans heavily toward RNA viruses, which have dominated recent pandemics. Thousands of RNA virus species have been identified, but only a small subset infects humans, and many of those are zoonotic—spilling over from animals but not spreading onward from person to person. Ars Technica reports that roughly two-thirds of viruses on the list fall into that category, making them alarming in headlines but limited in the outbreaks they can sustain.

The more expensive problem is the smaller set of viruses that already transmit among humans. A virus that can move through cities and transport networks does not need to “evolve transmissibility” to cause a crisis; it only needs an opportunity. The article points to how outbreaks can change character when they shift from remote settings to dense populations, citing the 2014 West Africa outbreak of Zaire ebolavirus as an example of what happens when geography and connectivity change.

The catalog also pushes back against a popular fear: that a purely zoonotic RNA virus will gradually mutate into a human-to-human pathogen after repeated spillovers. Ars Technica notes the researchers’ claim that there is no documented example of an RNA virus making that specific transition, with rabies offered as a counterexample—many human cases, no sustained human transmission. The risk, on this telling, concentrates instead in viruses that are already capable of human spread but have not yet been tested against modern mobility and public-health weak points.

The list is meant to be actionable: a short roster of “outbreak viruses” is presented as a strong predictor of which pathogens later become public-health emergencies, and the article notes that several original entries—such as Zika, chikungunya, Oropouche viruses and mpox—have since driven major epidemics. That makes the catalog less a speculative doomsday register than a budget document: it implies that preparedness depends on funding the unglamorous work of monitoring known viral families and building response capacity before the next airport-and-hospital chain reaction begins.

Ars Technica describes the project as an attempt to turn viral discovery from a series of surprises into a managed queue. It still leaves governments with the same practical test: whether they will pay for surveillance and readiness when the most dangerous pathogens are, by definition, not yet causing an emergency.