Research and analysis

Variants: distribution of case data, 25 February 2022

Updated 24 June 2022

Surveillance overview

Initially, the surveillance of coronavirus (COVID-19) infections in England was based on any number of positive samples from the same person being grouped together, so that the person was only counted once in the national figures and reported using the date of the first positive result from that individual.

From 31 January 2022, an ‘episode’ definition was introduced, grouping all positive test results up to and including 90 days apart into a single episode. Positive test results which are more than 90 days apart are now classed as separate episodes.

Due to the correction of misclassified genotyping results, there may be small reductions in variant numbers.

UK total distribution

Variant* Other names by which this variant may be known** Lineage Total confirmed (sequencing) and probable (genotyping) cases¥ New cases since last update (data up to 16 February 2022)
Alpha VOC-20DEC-01 B.1.1.7 281,205 -1
Beta§ VOC-20DEC-02 B.1.351 1,063§ 0
Gamma VOC-21JAN-02 P.1 292 -2
Delta VOC-21APR-02 B.1.617.2 AY.1 AY.2 1,730,087 +307
VUI-21OCT-01*** VUI-21OCT-01 A.Y 4.2 123,080 +262
Omicron VOC-21NOV-01 B.1.1.529 1,643,742 +100,292
Zeta VUI-21JAN-01 P.2 50 0
VUI-21FEB-03 VUI-21FEB-03 B.1.525 (previously designated UK1188) 495 0
VUI-21FEB-04 VUI-21FEB-04 B.1.1.318 374 0
Theta VUI-21MAR-02 P.3 9 0
Kappa VUI-21APR-01 B.1.617.1 465 0
VUI-21APR-03 VUI-21APR-03 B.1.617.3 18 0
VUI-21MAY-02 VUI-21MAY-02 C.36.3 138 0
Lambda VUI-21JUN-01 C.37 8 0
Omicron BA.2 VUI-22JAN-01 B.1.1.529.BA.2 37,937 +14,393

*Information pertaining to VUI-21MAR-01, B1.324.1 with E484K has been removed as this variant has been reclassified as provisionally extinct.
Variants VUI-21FEB-01 (A.23.1 with E484K), and VOC-21FEB-02 (Alpha with E484K) are provisionally extinct (not detected for 12 weeks in the UK or in GISAID) therefore they will no longer be included in the publication from 12 November 2021.
Variant VUI-21MAY-01, AV.1 has been removed as of 3 December 2021 as it has been classified as provisionally extinct.
Variant VUI-21JUL-01 (Mu) has been removed as of 17 February 2022 as it has been classified as provisionally extinct.

**WHO naming has been included where available.

¥Confirmed individuals are confirmed COVID-19 cases with a validated sequencing result meeting the confirmed case definitions outlined in the sections below. Probable individuals are confirmed COVID-19 cases with a genotyping result where sequencing confirmation is awaited or not available. Published figures include genotyping assay data for England, using a combination of highly specific mutations as an indicator of a probable variant. Genotyping assay data is currently only available for Alpha, Beta (for specimen dates up to and including 30 June 2021), Delta and Gamma.

‡Of which 780 had the K417N mutation.

§Due to having identical genotyping profiles, since 1 July Beta and Mu cases identified by genotyping have been categorised as ‘Beta or Mu’. In addition to the above numbers, a further 21 ‘Beta or Mu’ provisional genotyping cases have been identified.

***Confirmed VOC-21APR-02 with at least 2 VUI-21OCT-01 lineage defining positions called as alternate (variant) base and all other defining positions reported as N (unknown) or mixed bases.

Differences between a variant of concern and a variant under investigation

SARS-CoV-2 variants, if considered to have concerning epidemiological, immunological or pathogenic properties, are raised for formal investigation. At this point they are designated variant under investigation (VUI) with a year, month, and number. Following a risk assessment with the relevant expert committee, they may be designated variant of concern (VOC).

Changes in nomenclature

The previous variant names frequently include similar numbers with similar or repeating patterns. This makes referring to them verbally challenging. To overcome this challenge, a revised nomenclature has been agreed involving dropping the first 2 numbers of the year and replacing the 2-month numbers with a 3-letter abbreviation. This shortens the name and reduces the degree of repeated sequences of numbers. The table containing surveillance overview ‘UK total distribution’ contains a list of new variant names alongside previous or other names in use for VOCs and VUIs.

Note on Omicron (VOC-21NOV-01 and VUI-22JAN-01)

As genotyping assays cannot distinguish between Omicron BA.1 (VOC-21NOV-01), and Omicron lineage BA.2 (VUI-22JAN-01) genomes, Omicron (VOC-21NOV-01) includes cases of BA.1 and BA.2 genomes where those genomes were identified by genotyping only and not confirmed by genome sequencing.

Alpha

Surveillance overview

Total confirmed and probable cases
England 230,472
Northern Ireland 9,162
Scotland 29,127**
Wales 12,444
Total cases 281,205

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 5 VOC-20DEC-01 lineage defining positions are called as alternate (variant) base and all other defining positions reported as N (unknown) or mixed bases
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by polymerase chain reaction (PCR).

**Correction of misclassified genotyping results may appear as small reductions in variant numbers. There is one less case of Alpha reported compared to the last update (data up to 16 February 2022).

Beta

Surveillance overview

Total confirmed and probable cases
England 949
Northern Ireland 9
Scotland 62
Wales 43
Total cases 1,063

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case where:
• at least 4 VOC-20DEC-02 lineage defining positions are called as alternate (variant) base, and
• all other defining positions reported as N (unknown) or mixed bases 
or
• at least 5 of the 9 non-synonymous changes
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

Gamma

Surveillance overview

Total confirmed and probable cases
England 267**
Northern Ireland 0
Scotland 23
Wales 2
Total cases 292

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with:
• at least 5 lineage defining non-synonymous changes called as alternate base, and
• all other positions either N or mixed bases
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

**Correction of misclassified genotyping results may appear as small reductions in variant numbers. There are 2 fewer cases of Gamma reported compared to the last update (data up to 16 February 2022).

Delta

Surveillance overview

Total confirmed and probable cases
England 1,412,113
Northern Ireland 93,277
Scotland 133,597**
Wales 91,100
Total cases 1,730,087

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 4 variant defining changes called as alternate base
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

**Correction of misclassified genotyping results may appear as small reductions in variant numbers. There are 23 fewer cases of Delta reported compared to the last update (data up to 16 February 2022).

VUI-21OCT-01

Surveillance overview

Total confirmed and probable cases
England 93,684
Northern Ireland 745**
Scotland 13,633
Wales 15,018
Total cases 123,080

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case that is confirmed VOC-21APR-02 with at least 2 VUI-21OCT-01 lineage defining positions called as alternate (variant) base and all other defining positions reported as N (unknown) or mixed bases.
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

**Correction of misclassified genotyping results may appear as small reductions in variant numbers. There are 6 fewer cases of VUI-21OCT-01 reported compared to the last update (data up to 16 February 2022).

Omicron

Surveillance overview

Total confirmed and probable cases
England 1,358,184
Northern Ireland 80,138
Scotland 124,981
Wales 80,439
Total cases 1,804,018

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 10 lineage defining non-synonymous changes called as alternate base and no more than 7 defining positions called as wild-type
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.  

Zeta

Surveillance overview

Total confirmed and probable cases
England 44
Northern Ireland 0
Scotland 5
Wales 1
Total cases 50

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* case confirmed as infected with VUI-21JAN-01 through whole genome sequencing (WGS) where:
• results of all lineage defining non-synonymous changes called as alternate base
or
• 6 of 7 non-synonymous changes called as alternate base, and
• remaining position either N or mixed bases
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

VUI-21FEB-03

Surveillance overview

Total confirmed and probable cases
England 443
Northern Ireland 2
Scotland 40
Wales 10
Total cases 495

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with:
• at least 5 lineage defining non-synonymous changes called as alternate base, and
• all other positions either N or mixed bases
Probable (genotyping) COVID-19* confirmed case with a genotyping result where sequencing confirmation is awaited or not available
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

VUI-21FEB-04

Surveillance overview

Total confirmed and probable cases
England 323
Northern Ireland 40
Scotland 11
Wales 0
Total cases 374

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with:
• at least 5 lineage defining non-synonymous changes called as alternate base, and
• all other positions either N or mixed base
or
• at least 5 of the 9 non-synonymous changes
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

Theta

Surveillance overview

Total confirmed and probable cases
England 6
Northern Ireland 0
Scotland 3
Wales 0
Total cases 9

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with:
• at least 7 variant defining changes called as alternate base, and
• all other positions either N or mixed base
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

Kappa

Surveillance overview

Total confirmed and probable cases
England 419
Northern Ireland 4
Scotland 27
Wales 15
Total cases 465

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with:
• at least 6** variant defining changes called as alternate base, and
• all other positions either N or mixed base
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.
**Due to overlap with Delta sequences, the case definition of Kappa sequences was changed on 27 August 2021.

VUI-21APR-03

Surveillance overview

Total confirmed and probable cases
England 15
Northern Ireland 0
Scotland 0
Wales 3
Total cases 18

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with:
• at least 8 variant defining changes called as alternate base, and
• all other positions either N or mixed base
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

VUI-21MAY-02

Surveillance overview

Total confirmed and probable cases
England 128
Northern Ireland 2
Scotland 4
Wales 4
Total cases 138

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 5 variant defining changes called as alternate base, and
• all other positions either N or mixed base.
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

Lambda

Surveillance overview

Total confirmed and probable cases
England 8
Northern Ireland 0
Scotland 0
Wales 0
Total cases 8

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 5 VUI-21JUN-01 lineage defining positions are called as alternate (variant) base and all other defining positions reported as N (unknown) or mixed bases.
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.

Omicron BA.2 (VUI-22JAN-01)

Surveillance overview

Total confirmed and probable cases
England 31,905
Northern Ireland 2,071
Scotland 2,624
Wales 1,337
Total cases 37,937

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 10 lineage defining non-synonymous changes called as alternate base and no more than 3 defining positions called as wild-type.
*A confirmed COVID-19 case: a case where the individual is confirmed to be infected with SARS-CoV-2 by PCR.