Virus names are decided by the International Committee on Taxonomy of Viruses (ICTV), a body of expert virologists that reviews, approves, and ratifies every formal virus species name used in science. The process is more structured than most people realize, and it recently underwent its biggest overhaul in decades: in 2021, the ICTV adopted a standardized binomial naming system for all virus species, bringing viruses in line with the genus-plus-epithet format familiar from the naming of animals and plants. Understanding how this works clears up a lot of the confusion people feel when they encounter names like SARS-CoV-2, mpox, or Ebola and wonder who decided what.
The Committee Behind Every Virus Name
The ICTV has been the sole authority on virus taxonomy since its founding in the 1960s. It maintains an official, publicly available list of every recognized virus taxon and its approved name. Proposals for new virus species, genera, families, or higher-level groupings go through study groups made up of specialists in a particular virus family, then move to the ICTV Executive Committee for approval, and finally face a ratification vote by the full ICTV membership. Only after that vote does a name become official.
This is not a small operation. In a single 2024 ratification round, the ICTV membership voted on 203 taxonomic proposals. Those proposals added one new phylum, nine new orders, 51 new families, 820 new genera, and 3,547 new species to the official taxonomy. All 203 proposals passed.
The Move to Binomial Names
For most of virology’s history, virus species names were a grab bag. Some were Latinized, some were plain English, and many were simply the common name of the virus with a few extra words tacked on. The species containing the Ebola virus, for instance, was called “Zaire ebolavirus,” while HIV’s species was “Human immunodeficiency virus 1.” These names followed no universal pattern, which made the system look haphazard compared to the tidy binomial nomenclature used for bacteria, fungi, and every other branch of life.
In 2021, after years of discussion and community consultation, the ICTV formally adopted a binomial format: each virus species name now consists of a genus name followed by a free-form species epithet. After a three-year transition period, every previously assigned species name that did not fit the binomial format has been converted. The epithet does not have to be Latin; it can draw on geography, morphology, the host organism, or essentially any distinguishing feature. The key constraint is that the genus name comes first and the epithet follows, giving every virus species name a consistent two-part structure.
This was not a cosmetic change. A standardized format makes it far easier to write software that parses virus names, to build databases that organize them, and to communicate unambiguously across languages. Before binomials, a researcher searching a database for a virus species had to know exactly which idiosyncratic string of words the ICTV had assigned, and those strings did not follow predictable rules. Now the rules are predictable.
Virus Name Versus Disease Name
One of the most persistent sources of public confusion is that the virus and the disease it causes often have different names assigned by different organizations. The ICTV names the virus (and the species it belongs to). The World Health Organization (WHO) names the disease. These two bodies coordinate but operate independently, and their naming priorities differ.
The clearest example is the pandemic coronavirus. In early 2020, the ICTV’s Coronaviridae Study Group classified the new pathogen as a sister lineage of the original SARS virus within the species Severe acute respiratory syndrome-related coronavirus, and designated it SARS-CoV-2. The WHO, meanwhile, named the disease COVID-19. The virus and the disease are not the same thing, and their names reflect different considerations: the ICTV’s name captures the virus’s evolutionary relationship to earlier SARS coronaviruses, while the WHO’s disease name was chosen to be easy to pronounce and free of geographic or animal associations that could fuel stigma.
The ICTV also proposed a specific naming convention for individual isolates of SARS-CoV-2, following the format: SARS-CoV-2/host/location/isolate/date. That convention lets researchers track a particular sample back to when and where it was collected, a layer of detail that sits below the species level and serves a practical purpose in epidemiology and genomics.
When Names Carry Stigma
Disease and virus names have real-world consequences for the communities they become associated with. The WHO has formal guidance discouraging the use of geographic locations, animal species, or cultural references in new disease names, specifically to avoid the kind of stigmatization that has historically followed outbreaks.
A vivid recent example is mpox. The disease formerly known as monkeypox was renamed “mpox” in November 2022, during an outbreak that had already generated significant misinformation and prejudice. The old name was considered misleading on multiple levels: the virus’s natural reservoir is rodents, not monkeys, and the name’s associations were being weaponized in harmful ways. The renaming was a WHO decision about the disease name, not an ICTV decision about the virus taxonomy, but it illustrates how closely the two naming tracks interact in public health.
Virus taxonomists themselves are generally not in the business of policing colloquial usage. Researchers still say “Ebola virus” in conversation and in papers, even though the formal species name in the ICTV taxonomy has been updated to binomial format. The ICTV’s binomial system governs the official species designation; common names for the viruses themselves persist in everyday scientific and clinical language. This dual-track reality, where a formal name and a common name coexist, is the norm rather than the exception.
How a Proposal Actually Works
If you discover a new virus and want it formally recognized, you do not simply email the ICTV. The process starts with gathering enough biological and genomic evidence to demonstrate that the virus is genuinely distinct from everything already classified. You then write a taxonomic proposal, which is a structured document arguing for where the virus belongs in the hierarchy and what its species name should be.
That proposal goes to the relevant ICTV study group. Study groups are organized around virus families or larger groupings, and they are staffed by researchers with deep expertise in those particular viruses. The study group reviews the evidence, may ask for revisions, and eventually votes on whether to forward the proposal to the Executive Committee. The Executive Committee reviews all forwarded proposals and holds its own approval vote. Finally, the full ICTV membership ratifies the batch. This multi-stage process means that a single new species name can take a year or more to become official, and contentious reclassifications can take considerably longer.
The ICTV does not require that a virus be cultured in a lab or that a physical specimen exist in a reference collection. Metagenomic discoveries, where a virus genome is assembled from environmental sequencing data without ever isolating the virus itself, are eligible for formal classification. This has opened the floodgates: genomic surveys of ocean water, soil, and animal microbiomes have revealed thousands of previously unknown viral lineages, and the ICTV has been working to classify them at an accelerating pace. The 3,547 new species ratified in a single 2024 round reflect this deluge.
Naming Bacteriophages
Viruses that infect bacteria, called bacteriophages or simply phages, have their own naming quirks. Classification of phages falls to the Bacterial and Archaeal Viruses Subcommittee (BAVS) within the ICTV. For decades, phages were sorted into families based largely on their physical shape under an electron microscope: tailed phages with long tails went into one family, those with short tails into another, and so on. These morphology-based families, particularly Siphoviridae, Myoviridae, and Podoviridae, became deeply embedded in the phage research literature.
In 2022, the ICTV abolished those families. Genomic analysis had shown that the old shape-based groupings were not evolutionarily coherent; viruses lumped together because they looked similar were often not closely related at all. The overhaul replaced these families and the order Caudovirales with a new set of taxa based on genetic relationships. In that same round of changes, one order, 22 families, 30 subfamilies, 321 genera, and 862 species were newly created, promoted, or rearranged. Researchers who had spent their careers talking about “siphoviruses” suddenly had to learn a new vocabulary, and older papers referencing the abolished families became harder to cross-reference with the current taxonomy.
Choosing a name for a new phage before submitting it for formal classification is not trivial either. Whatever informal name a researcher gives a phage when they first describe it in a paper tends to stick in databases and eventually gets incorporated into the official taxon name. Naming a phage after a pop-culture reference or an inside joke might seem harmless, but those names can end up in regulatory documents and medical records. The BAVS encourages researchers to pick names that are informative and unlikely to cause confusion down the road.
Giant Viruses and the Edges of Classification
Some viruses strain the classification system simply by being weird. The nucleocytoplasmic large DNA viruses (NCLDVs) of eukaryotes are a sprawling group that includes the poxviruses, the iridoviruses, the massive mimiviruses, and the even more massive pandoraviruses. Some of these have genomes larger than those of small bacteria, which challenges longstanding assumptions about what a virus is supposed to be.
Taxonomically, the group has been proposed as a single order called “Megavirales,” but this has not been universally adopted by the ICTV. Some members of the group, such as pandoraviruses, molliviruses, and faustoviruses, remain unaccounted for in the official virus taxonomy. They exist in a kind of classificatory limbo: studied extensively, discussed in the literature, but not yet slotted into a ratified taxon. This happens because the ICTV requires a formal proposal for every new taxon, and the genomic relationships within the NCLDVs are still being worked out. Some lineages form clean monophyletic groups that map neatly onto existing families. Others sit within larger groups that appear to be evolutionary mosaics, making it hard to draw clean taxonomic boundaries.
The practical consequence is that if you read a paper about a giant virus, the taxonomic names you encounter may not match what the ICTV officially recognizes. Researchers use provisional or proposed names as a matter of necessity, and those names eventually either get ratified or replaced.
When Taxonomy Meets Databases
The ICTV maintains its own master list of approved taxa, but the databases that most researchers actually use day to day, particularly the NCBI’s viral genome resources, have their own classification systems that do not always line up. The NCBI taxonomy is built to organize sequence data and is updated on a rolling basis, whereas the ICTV taxonomy is updated in annual batches through the formal ratification process. This mismatch creates friction.
Efforts to bridge the gap have been ongoing for years. One tool, called ORION-VIRCAT, was built specifically to map between ICTV and NCBI taxonomies, automatically joining over 617,000 entries from the NCBI viral genome resource to ICTV naming conventions. Other projects have extended the ICTV taxonomy downward to strain and isolate level and linked those entries to NCBI sequence data and journal references. The goal is a seamless chain: you find a virus genome in a database, and you can immediately see its ICTV-approved species name, its higher taxonomy, and links to the primary literature describing it.
That goal remains aspirational. In practice, a virus genome deposited in GenBank in 2015 may carry a species name that was abolished in 2022, and the database entry may not have been updated. Researchers searching for sequences need to know both the old and new names, or use mapping tools, to get complete results. The binomial naming reform should help in the long run, because standardized two-part names are easier for software to parse and reconcile than the old free-form names. But the transition period is messy, and older literature will carry outdated taxonomy indefinitely.
Names in Regulatory and Biosafety Documents
Virus names do not only matter in research papers. They show up in biosafety regulations, containment-level guidelines, import permits, and public health law. When those documents use imprecise or outdated virus names, real problems follow. The UK’s Advisory Committee on Dangerous Pathogens (ACDP), for instance, maintains a list of containment restrictions for microbiological pathogens. That list has historically used a confusing mix of common virus names and formal species terms, leading to practical headaches for laboratory managers trying to determine which containment level applies to a given pathogen.
The move to standardized binomial species names offers a fix. If regulatory documents adopt the ICTV’s binomial format, each entry on a biosafety list maps cleanly to a defined taxon at the species or below-species level. That format would also bring virus entries into line with how bacteria, fungi, and amoebae are already listed in the same documents, eliminating the inconsistency that currently makes the virus sections harder to use. Whether regulatory agencies will actually update their documents to match the new nomenclature is a separate question. Bureaucracies tend to move slowly, and some of these lists have not been substantially revised in years.
Below-Species Classification and Its Gaps
The ICTV’s authority formally extends down to the species level. Below that, things get complicated. Variants, strains, serotypes, genotypes, and isolates are all terms used routinely by virologists and clinicians, but they do not have universally standardized definitions in the ICTV framework. Different virus communities use these terms differently: an “influenza strain” and an “HIV strain” carry different practical meanings, and neither maps to a formal ICTV rank.
This gap matters because much of clinical virology operates below the species level. The difference between SARS-CoV-2 Omicron and Delta is not a species-level distinction; both are the same virus species. But the clinical and epidemiological differences between them were enormous. The ICTV has been discussing whether and how to formalize below-species ranks, and some researchers have argued that the current system’s silence on sub-species terminology leads to confused regulatory documents and inconsistent communication. The debate is active and unresolved: formalizing below-species ranks would be useful for clarity, but it would also mean the ICTV taking on a vastly larger workload, since the number of recognized strains and variants dwarfs the number of recognized species.
For now, below-species naming remains largely a matter of convention within individual research communities. The WHO names variants of concern for pandemic viruses using Greek letters. Influenza researchers use a well-established system of subtype designations. Hepatitis virologists use genotype numbering. These systems work well enough within their domains but are not interoperable, and there is no single authority coordinating them the way the ICTV coordinates species-level naming.