Going by the Greek alphabet, the next names should have been "Nu" and "Xi" but the WHO skipped them and went on to call the latest coronavirus variant "Omicron".
But why? Was it to avoid similarities with Chinese President Xi Jinping's name?
Before the World Health Organization named Omicron as a variant "of concern" on Friday, the last identified variant was the Mu variant, named after the 12th out of 24 letters in the Greek alphabet.
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Nu and Xi, the 13th and 14th letters, were next in line.
But in a statement to Associated Press on Saturday, the WHO said: "'Nu' is too easily confounded with 'new', and 'Xi' was not used because it is a common last name."
It said its "best practices for naming disease suggest avoiding causing offence to any cultural, social, national, regional, professional or ethnic groups".
The naming of the virus has been controversial in the past, with former US president Donald Trump and his allies repeatedly referring to the coronavirus as the "China virus" or "Wuhan virus" despite protests from Beijing that the name would "stigmatise" the country and contribute to anti-Asian sentiment.
On Saturday, Trump's son Donald Trump Jnr tweeted: "As far as I'm concerned the original [name] will always be the Xi variant."
Republican Senator Ted Cruz also suggested in a tweet that Omicron's name showed that the WHO was "scared of the Chinese Communist Party".
The WHO has faced various accusations that it gave in to pressure from China over the coronavirus, which was first reported from the Chinese city of Wuhan in late December, 2019.
Controversies ranged from whether the WHO pushed China enough to provide data, to the exclusion of Taiwan, which Beijing sees as a breakaway province, from key meetings related to pandemic control.
The health body announced its adoption of the Greek alphabet system to describe variants of coronavirus strains in May this year, saying these labels were simple and easy to say and remember. It also noted that associating variants with places was "stigmatising and discriminatory".
In China, a number of Chinese characters which would be pronounced as "Xi" in different tones are used as surnames.
According to data from the Ministry of Public Security in February, the Chinese president's surname is the 296th most common family name in the country.
Two other surnames that would also be read as "Xi" but read in different tones were more common, ranking 169 and 228 out of the top 300 surnames in China.
This article originally appeared in the South China Morning Post (SCMP), the most authoritative voice reporting on China and Asia for more than a century. For more SCMP stories, please explore the SCMP app or visit the SCMP's Facebook and Twitter pages. Copyright © 2021 South China Morning Post Publishers Ltd. All rights reserved.
Copyright (c) 2021. South China Morning Post Publishers Ltd. All rights reserved.