Theta variant, also known as lineage P.3, is one of the

variants Variant may refer to: In arts and entertainment * ''Variant'' (magazine), a former British cultural magazine * Variant cover, an issue of comic books with varying cover art * ''Variant'' (novel), a novel by Robison Wells * " The Variant", 2021 e ...

SARS-CoV-2 Severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) is a strain of coronavirus that causes COVID-19 (coronavirus disease 2019), the respiratory illness responsible for the ongoing COVID-19 pandemic. The virus previously had a ...

, the virus that causes

COVID-19 Coronavirus disease 2019 (COVID-19) is a contagious disease caused by a virus, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first known case was COVID-19 pandemic in Hubei, identified in Wuhan, China, in December ...

. The variant was first identified in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

on February 18, 2021, when two mutations of concern were detected in

Central Visayas Central Visayas ( ceb, Tunga-tungang Kabisay-an; tl, Gitnang Kabisayaan) is an administrative region in the Philippines, numerically designated as Region VII. It consists of four provinces: (Cebu, Bohol, Negros Oriental, and Siquijor) and thr ...

. It was detected in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

on March 12, 2021, when a traveler from the Philippines arrived at

Narita International Airport Narita International Airport ( ja, 成田国際空港, Narita Kokusai Kūkō) , also known as Tokyo-Narita, formerly and originally known as , is one of two international airports serving the Greater Tokyo Area, the other one being Haneda Airport ...

Tokyo Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...

. It is distinct from those first discovered in the United Kingdom, South Africa, and Brazil, and is thought to pose a similar threat. The variant is more resistant to

neutralizing antibodies A neutralizing antibody (NAb) is an antibody that defends a cell from a pathogen or infectious particle by neutralizing any effect it has biologically. Neutralization renders the particle no longer infectious or pathogenic. Neutralizing antibod ...

, including those gained through vaccination, like how the South African and Brazilian variants appear to be. Under the simplified naming scheme proposed by the

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...

, P.3 has been labeled Theta variant, and was considered a ''variant of interest'' (VOI), but not a

variant of concern The term variant of concern (VOC) for SARS-CoV-2, which causes COVID-19, is a category used for variants of the virus where mutations in their spike protein receptor binding domain (RBD) substantially increase binding affinity (e.g., N501Y) in ...

. As of July 2021, Theta is no longer considered as a variant of interest by the WHO.

Classification

Naming

On March 17, 2021,

Public Health England Public Health England (PHE) was an executive agency of the Department of Health and Social Care in England which began operating on 1 April 2013 to protect and improve health and wellbeing and reduce health inequalities. Its formation came as a ...

(PHE) named Lineage P.3 ''VUI-21MAR-02''. On June 1, 2021, the

(WHO) named lineage P.3 as Theta variant.

Mutations

File:SARS-CoV-2_Theta_variant.svg, Amino acid mutations of SARS-CoV-2 Theta variant plotted on a genome map of SARS-CoV-2 with a focus on the spike. A total of 14 amino acid replacements were observed in all samples (labeled in below), including seven

spike protein In virology, a spike protein or peplomer protein is a protein that forms a large structure known as a spike or peplomer projecting from the surface of an enveloped virus. as cited in The proteins are usually glycoproteins that form dimers or ...

mutations. Among the spike protein mutations, four have been previously associated with lineages of concern (i.e., E484K, N501Y, D614G, and P681H) while three additional replacements were observed towards the C-terminal region of the protein (i.e., E1092K, H1101Y, and V1176F). A single amino acid replacement at the

N-terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

of ORF8 (i.e., K2Q) was also found in all samples. Three other mutations were seen in 32 of the 33 samples (labeled in ) including a three-amino acid deletion at the spike protein positions 141 to 143. Lastly, five synonymous mutations (labeled in ) were also detected in all of the cases.

History

On February 18, 2021, the

Department of Health A health department or health ministry is a part of government which focuses on issues related to the general health of the citizenry. Subnational entities, such as states, counties and cities, often also operate a health department of their ow ...

of the

confirmed the detection of two mutations of COVID-19 in

after samples from patients were sent to undergo genome sequencing. The mutations were later named as E484K and N501Y, which were detected in 37 out of 50 samples, with both mutations co-occurrent in 29 out of these. There were no official names for the variants and the full sequence was yet to be identified. On March 12, 2021,

detected the variant on a traveler from the Philippines. On March 13, 2021, the Department of Health confirmed the mutations constituted a new variant, which was designated as lineage P.3. On the same day, it also confirmed its first case of

lineage P.1 The Gamma variant (P.1) was one of the variants of SARS-CoV-2, the virus that causes COVID-19. This variant of SARS-CoV-2 has been named lineage P.1 and has 17 amino acid substitutions, ten of which in its spike protein, including these thre ...

in the country. Although the lineages P.1 and P.3 stem from the same lineage B.1.1.28, the department said that the impact of lineage P.3 on vaccine efficacy and transmissibility is yet to be ascertained. On March 17, 2021, the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

confirmed its first two cases, where

(PHE) termed it VUI-21MAR-02. On April 30, 2021,

Malaysia Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...

detected 8 cases of lineage P.3 in

Sarawak Sarawak (; ) is a States and federal territories of Malaysia, state of Malaysia. The largest among the 13 states, with an area almost equal to that of Peninsular Malaysia, Sarawak is located in northwest Borneo Island, and is bordered by the M ...

Statistics

Notes

References

External links

PANGO lineages: New Variant Report - Report on global distribution of lineage B.1.1.7

GISAID sequencing data base – Tracking of COVID-19 variants
{{authority control S8 COVID-19 pandemic in the Philippines