Variants of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19), has a lot of variants. Some of them are important because of increased transmission and vaccines being less effective on them. This article discusses relevant variants of SARS-CoV-2 and mutations in these variants.

The variant WIV04/2019   is most closely related to the original virus when it began infecting humans.

Overview 
There are a lot of lineages of SARS-CoV-2. Lineages are variants that are genetically the same.

Nomenclature 

There's no consistent nomenclature for SARS-CoV-2. Variants are usually refered to by the country where the variant came from. For example, B.1.1.7 is usually called the "UK variant."

Criteria for importance 
Viruses generally mutate over time, creating new variants. When a new variant grows in a population, it's labeled as an "emerging variant".

Some of the potential consequences of emerging variants are the following:

 Increased transmissibility
 Increased Morality (death).
 Ability to evade natural immunity (e.g., causing reinfections)
 Ability to infect vaccinated people

Notable variants

Cluster 5 

In early November 2020, Cluster 5, also referred to as ΔFVI-spike by the Danish State Serum Institute (SSI), was discovered in Northern Jutland, Denmark, and is believed to have been spread from minks to humans via mink farms. On 4 November 2020, it was announced that the mink population in Denmark would be culled to prevent the possible spread of this mutation and reduce the risk of new mutations happening. A lockdown and travel restrictions were introduced in seven municipalities of Northern Jutland to prevent the mutation from spreading, which could compromise national or international responses to the COVID-19 pandemic. By 5 November 2020, some 214 mink-related human cases had been detected.

The World Health Organization (WHO) has stated that cluster 5 has a "moderately decreased sensitivity to neutralizing antibodies". SSI warned that the mutation could reduce the effect of COVID-19 vaccines under development, although it was unlikely to render them useless. Following the lockdown and mass-testing, SSI announced on 19 November 2020 that cluster 5 in all probability had become extinct. As of 1 February 2021, authors to a peer-reviewed paper, all of whom were from the SSI, assessed that cluster 5 was not in circulation in the human population.

Lineage B.1.1.7 / Variant of Concern 20DEC-01 

This variant was first detected in October 2020 during the COVID-19 pandemic in the United Kingdom from a sample taken the month before in Kent. Lineage B.1.1.7,  It's correlated with a big increase in COVID-19 infection in United Kingdom, partly because of the N501Y mutation. There is some evidence that this variant has  40%–80% increased transmissibility and an increase in deadliness.

Variant of Concern 21FEB-02 
Variant of Concern 21FEB-02 (previously written as VOC-202102/02), described by Public Health England (PHE) as "B.1.1.7 with E484K" is the B.1.1.7 variant with  an additional E484K mutation. As of 17 March 2021, there are 39 confirmed cases of VOC-21FEB-02 in the UK. On 4 March 2021, scientists reported B.1.1.7 with E484K mutations in the state of Oregon. It seems that this combination happened randomly in Oregon, instead of coming from the UK.

Lineage B.1.1.317 
B.1.1.317 is not a variant of concern, but Queensland Health forced 2 people in hotel quarantine in Brisbane, Australia to go through an extra 5 days quarantine on top of the mandatory 14 days after it was confirmed they were infected with this variant.

Lineage B.1.1.318 
Lineage B.1.1.318 was detected on 24 February 2021. 16 cases of it have been detected in the UK.

Lineage B.1.351 

On 18 December 2020, the 501.V2 variant, also known as 501.V2, 20H/501Y.V2 (formerly 20C/501Y.V2), VOC-20DEC-02 (formerly VOC-202012/02), or lineage B.1.351, was first detected in South Africa and reported by the country's health department. Researchers and officials reported that the variant is more likely to make young people very sick. The South African health department also said that the variant may be driving the second wave of the COVID-19 epidemic in the country.

Scientists said that the variant has many mutations that allow it to attach more easily to human cells because of the following three mutations in the receptor-binding domain (RBD) in the spike glycoprotein of the virus: N501Y, K417N, and E484K. The N501Y mutation has also been detected in the United Kingdom.

Lineage B.1.429 / CAL.20C 
Lineage B.1.429, also known as CAL.20C, has by five distinct mutations (I4205V and D1183Y in the ORF1ab-gene, and S13I, W152C, L452R in the spike proteins S-gene). B.1.429 might be more transmissible. The CDC has listed B.1.429 and the related B.1.427 as "variants of concern," and says that they have a ~20% increase in transmissibility.

B.1.429 was first discovered in July 2020 by researchers at the Cedars-Sinai Medical Center, California, in one of 1,230 virus samples collected in Los Angeles County since the start of the COVID-19 epidemic. It wasn't detected again until September when it reappeared among samples in California, but numbers remained very low until November. In November 2020, the CAL.20C variant accounted for 36 percent of samples collected at Cedars-Sinai Medical Center, and by January 2021, the CAL.20C variant was 50 percent of samples.

Lineage B.1.525 
B.1.525, also called VUI-21FEB-03 (previously VUI-202102/03) by Public Health England (PHE) and formerly known as UK1188, doesn't have the same N501Y mutation found in B.1.1.7, 501.V2 and P.1, but has the same E484K-mutation as found in the P.1, P.2, and 501.V2 variants. B.1.525 is different from all other variants by having both the E484K-mutation and a new F888L mutation. As of March 5, it had been found in 23 countries, including the UK, Denmark, Finland, Norway, Netherlands, Belgium, France, Spain, Nigeria, Ghana, Jordan, Japan, Singapore, Australia, Canada, Germany, Italy, Slovenia, Austria, Malaysia, Switzerland, the Republic of Ireland and the US.

Lineage P.1 

Lineage P.1, termed Variant of Concern 21JAN-02 (formerly VOC-202101/02) by Public Health England and 20J/501Y.V3 by Nextstrain, was found in Tokyo on 6 January 2021 by the National Institute of Infectious Diseases (NIID). The new lineage was first identified in four people who arrived in Tokyo having travelled from the Brazilian Amazonas state on 2 January 2021. On 12 January 2021, the Brazil-UK CADDE Centre confirmed 13 local cases of the P.1 new lineage in the Amazon rain forest. This variant of SARS-CoV-2 has been named P.1 lineage (although it is a descendant of B.1.1.28, the name B.1.1.28.1 is not permitted and thus the resultant name is P.1), and has 17 unique amino acid changes, 10 of which in its spike protein, including the three concerning mutations: N501Y, E484K and K417T.

A study of samples from Manaus between November 2020 and January 2021, showed the P.1 lineage to be 1.4–2.2 times more transmissible. The variant is also 10–80% more deadly.

A vaccinated person has a higher risk of getting a mild P.1 infection while still being 100% protected against hospitalisation or death.

Preliminary data from two studies indicate that the Oxford–AstraZeneca vaccine is effective against the P.1 variant, although the exact level of efficacy has not yet been released. Preliminary data from a study conducted by Instituto Butantan suggest that CoronaVac is effective against the P.1 variant as well, and the study will be expanded to obtain definitive data.

Differential vaccine effectiveness 

 RaTG13, the closest known relative to SARS-CoV-2

Notes

References

Other websites 

 
 
 

Disease-related lists
SARS-CoV-2