SNA (Tokyo) — Less than two weeks after the Shingetsu News Agency issued its SNA Covid Variant Handbook, the World Health Organization stepped up to plate and belatedly offered its own new nomenclature.

In recognition of this development, we reissued a revised version of our handbook, adopting the new WHO nomenclature and relating it to previous classification and naming systems, as well as contextualizing to the specifically Japanese experience.

Here is the revised nomenclature, presenting each coronavirus variant chronologically in terms of when they were first confirmed as having arrived in Japan.

Covid-19: The first cases of what became the global pandemic emerged in Wuhan, China, in December 2019. The first cases in Japan were reported the following month, in January 2020. SNA will continue to describe the original coronavirus as Covid-19.

Covid Alpha Variant: Known previously as the UK or Kent Variant, or under the Pango nomenclature system as B.1.1.7, it was first identified in Kent county, England, in October 2020. The first Japan case was identified in December 2020. It contains the N501Y mutation. Some strains, though not others, contain the E484K mutation. It is known to be about 60% more transmissible than Covid-19 and possibly more lethal.

Covid Beta Variant: Known previously as the South Africa Variant, or under the Pango nomenclature system as B.1.351, it was first identified in Nelson Mandela Bay in October 2020. The first Japan case was identified in December 2020. It contains both the N501Y and E484K mutations. It is believed to be more transmissible than Covid-19.

Covid Gamma Variant: Known previously as the Brazil Variant, or under the Pango nomenclature system as P.1 or B.1.1.28.1, this variant was first identified in Japan in January 2021, carried by travelers from the Brazilian state of Amazonas. It contains both the N501Y and E484K mutations. It may be both more transmissible and more lethal than Covid-19, according to initial research.

Covid Theta Variant: Known previously as the Philippines Variant, or under the Pango nomenclature system as P.3, it was first detected in the Central Visayas region of the Philippines. The first Japan case was identified in March 2021. It contains both the N501Y and E484K mutations. It may be both more transmissible and more lethal than Covid-19.

Covid Epsilon Variant: Known previously as the California Variant, or under the Pango nomenclature system as B.1.427 or B.1.429 or sometimes as CAL.20C, it was first identified in July 2020 in Los Angeles, California. It contains the L452R mutation. The first Japan case was identified in Okinawa in April 2021. It may be more transmissible than Covid-19.

Covid Delta Variant: Known previously as the Indian Variant, or under the Pango nomenclature system as B.1.617.2, it was first identified in Maharashtra, India, in October 2020. The first Japan cases were identified in April 2021. It contains both the L452R and E484Q mutations. It is known to be the most transmissible variant to date, with early tests showing it to be about 60% more transmissible than the Alpha Variant.

Covid Lambda Variant: Known under the Pango nomenclature system as C.37, it was first identified in Peru in December 2020. The first Japan case was identified in July 2021. It contains the L452Q and other mutations. Early tests showed it to be more transmissible than the Alpha or Gamma variants, and possibly more resistant to the existing Covid vaccines.

Covid Mu Variant: Known under the Pango nomenclature system as B.1.621, it was first identified in Colombia in January 2021. It contains both the N501Y and E484K mutations. The first Japan case was identified in September 2021. Early tests showed it might be more resistant to the existing Covid vaccines.

Covid Kappa Variant: Known under the Pango nomenclature system as B.1.617.1, it was first identified in India in April 2021. It contains the L452R, E484Q, and P681R mutations. The first Japan case was identified in September 2021.

Covid Eta Variant: Known under the Pango nomenclature system as B.1.525, it was first identified in multiple countries in March 2021. It contains the E484K and F888L mutations. The first Japan case was identified in September 2021.

Covid Omicron Variant: Known under the Pango nomenclature system as B.1.1.529, it was first identified in South Africa in November 2021. It contains multiple mutations, and is believed to be particularly dangerous. The first Japan case was identified in November 2021.

This handbook is being updated in the future as new Covid variants are discovered in Japan and more detailed information becomes available.

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