Monkeypox variants assigned new names by WHO 

Monkeypox variants assigned new names by WHO
© iStock/Bill Oxford

A new system for naming variants of the monkeypox virus has been decided after a group of experts were convened by the World Health Organization (WHO). 

Monkeypox was first given its name in 1958 immediately after the discovery of the disease. However, it has been decided that going forward the naming of new variants of the virus should fall in line with current best practices. Current best practice dictates that the naming of newly identified diseases, viruses and variants should avoid any terms which may offend any geographic, regional, national social, ethnic, or professional. Naming methods should also minimise any negative impact on tourism, trade, travel and animal welfare. Traditionally, major variants were named based on the geographic regions they were known to circulate. 

The naming of a new virus is decided by the International Committee on the Taxonomy of Viruses (ICTV). The naming of new variants from existing pathogens is usually the result of a debate among scientists. To accelerate the naming process, WHO gathered virologists and health experts in an ad hoc meeting on 8 August 2022 to reach an agreement on the new terminology.  

How the naming process for monkeypox variants was decided

The meeting, which was made up of experts in pox virology and evolutionary biology, as well as representatives from research institutions from around the world, decided that the new clades monkeypox will be named using a system of Roman numerals. 

During the meeting, participants discussed the phylogeny and nomenclature of known and new variants of the monkeypox virus. The experts reviewed the characteristics and evolution of various monkeypox variants and their clinical and phylogenetic differences. The effects of the new naming system on future virological and evolutionary research were also considered by the panel.  

An agreement on new nomenclature was reached by the group that was in line with current best practices as to how new virus clades should be recorded on genome sequence repository sites. 

The new naming structure

As a result of the meeting, new names have been assigned to existing variants of the monkeypox virus. The Congo Basin variants have been renamed Clade one (I) and the West African variant will now be referred to as Clade Two (II).  

The new naming structure means new variants will be represented by a Roman numeral for the clade and a lower-case alphanumeric character for any subclades. This method will go into immediate effect.  

Whilst a new consensus has been reached for the naming of new clades, work continues on an overall renaming of the monkeypox virus. Assigning a new name to an existing disease is the responsibility of WHO and must be completed in accordance with the International Classification of Diseases and the WHO Family of International Health Related Classifications (WHO-FIC). WHO is holding an open consultation on the renaming of the monkeypox virus. Anyone who wishes to propose an alternative name can do so via the WHO website. 


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