The SARS-CoV-2 outbreak that once seemed far away has spread around the globe. As such, the most pressing questions on people’s minds are understandably health related—such as how easy it is to contract the virus and how to best prepare for an epidemic. Although the virus’s name may not be at the forefront of this ongoing health crisis, it is interesting to note how the virus got its name and what that means about the virus. A recent paper published by the consortium that took on the task of naming the virus yields interesting information about its identity.
Up until February 11, the same day that the disease caused by the coronavirus was named COVID-19 by the World Health Organization (WHO), the virus itself was referred to as 2019-nCoV. The announcement of the new name—SARS-CoV-2—came in the form of a bioRxiv preprint from the Coronaviridae Study Group (CSG) of the International Committee on Taxonomy of Viruses.
Now, the group’s work is explained more fully in a Nature Microbiology paper titled, “The species Severe acute respiratory syndrome-related coronavirus: classifying 2019-nCoV and naming it SARS-CoV-2” In this paper, the CSG noted that “based on phylogeny, taxonomy, and established practice, the CSG recognizes this virus as forming a sister clade to the prototype human and bat severe acute respiratory syndrome coronaviruses (SARS-CoVs) of the species Severe acute respiratory syndrome-related coronavirus, and designates it as SARS-CoV-2.” They also noted that, in order to facilitate communication, individual isolates should be named using the convention, SARS-CoV-2/host/location/isolate/date.
The paper describes the process involved in naming viruses, identifies potential causes of confusion over the nomenclature, and highlights the importance of careful characterization of emerging viruses.
The established practice for classification of a new virus is to assess its genetic relation to known viruses. There are currently 39 recognized and 10 tentative coronavirus species, many of them containing dozens or even hundreds of different viruses.
The work was led by John Ziebuhr, PhD, faculty, University Giessen, Germany and Alexander Gorbalenya, PhD, professor emeritus of applied bioinformatics in virology at Leiden University Medical Center, Leiden, Netherlands.
Together with colleagues, Ziebuhr and Gorbalenya assessed how closely the novel coronavirus is genetically related to these known coronaviruses. By comparing genomic data and specifically looking at variation in conserved proteins involved in virus replication, they find that the novel virus clusters with viruses of the species Severe acute respiratory syndrome-related coronavirus. This relationship has also been reported by other groups and is so close that the virus could be classified as belonging to this previously established species rather than representing a new species.
The novel virus has therefore been assigned the name SARS-CoV-2 based on these identified genetic links with viruses of the species Severe acute respiratory syndrome-related coronavirus. The species itself derived its name from the founding virus responsible for the 2002–2003 respiratory disease outbreak in humans: SARS-CoV, whose name, in turn, was based on the name given to the associated disease SARS.
Severe acute respiratory syndrome-related coronavirus is a species that contains hundreds of known viruses (predominantly isolated from humans and bats), all of which have their names derived from SARS-CoV. However, the authors explain that the reference to SARS in these names acknowledges the evolutionary links—rather than the clinical disease-based relationship—with the founding virus.
Currently available data characterizing SARS-CoV-2 indicate that the disease traits and transmission may vary from those reported for SARS-CoV. The authors propose that the emergence of SARS-CoV-2 should be considered completely independent from the SARS-CoV outbreak in 2002–2003. However, they emphasize that the two viruses are genetically closely related, and recommend studying the relationships of viruses within this species to help us to understand more about the biology and evolution of these human pathogens and their closest coronavirus relatives infecting bats and other animals.
The WHO assigned the name COVID-19 to denote the disease that is caused by SARS-CoV-2, which appears to be associated with a wide range of clinical features and outcomes. This uncoupling of disease and virus name offers a clear distinction between the virus and disease; the authors recommend not conflating the terms when referring to the viral outbreak and the clinical disease.
“Separating the names of the virus and the disease sends a message that disease is only one of many possible outcomes of various virus infections in individuals, including infections by SARS-CoV-2,” Gorbalenya told GEN. This complexity is broadly recognized by virologists and now it is also reflected in the name of this particular virus. In this respect, he continued, the public is better informed about advancements in virology, which “may take effort and time to reconcile with the predominant perception of viruses as the causative agents (and as extensions) of diseases.”
Although some have expressed that the naming of disease and virus could have had more coordination, the initial confusion seems to have settled and people have readily adopted that the SARS-CoV-2 virus causes the disease COVID-19.