Research and analysis

Variants: distribution of case data, 14 April 2022

Updated 24 June 2022

Changes to variant classification system

The UK Health Security Agency (UKHSA) has amended its variant classification system to give a clearer indication of which variants have significant changes in biological properties compared to the current dominant variant(s).

In the new system, the variant of concern (VOC) label will be assigned to variants which are currently emerging or circulating, and for which we have confirmed or can predict:

  • a detrimental change in biological properties (changes in transmissibility, severity or immune evasion) compared to the current dominant variant(s); and
  • a growth rate potentially compatible with maintaining transmission and/or displacing the current dominant variant

There will be no other categorisation of variants, including no variant under investigation (VUI) category. UKHSA will continue to designate new variants based on genomic features and growth, and these will receive a variant number (V-date-number).

Previous variants of concern that no longer meet the criteria above will be redesignated. These changes took effect as of 1 April 2022.

Surveillance overview

From 31 January 2022, UKHSA has reported episodes of infection in its coronavirus (COVID-19) surveillance. Previous surveillance of COVID-19 in England was based on positive samples from the same person grouped together, so that the person is only counted once and reported using the date of the first positive result.

The ‘episode’ definition introduced groups positive results up to and including 90 days apart into episodes. Positive test results which are more than 90 days apart will be classed as separate episodes.

The UKHSA methodology for reporting of COVID-19 cases varies between England and the devolved authorities. England and Scotland report 90-day infection episodes. Wales reports 42-day infection episodes. Northern Ireland reports data at individual level (only one infection episode is reported per person) but is working towards reporting 90-day infection episodes.

Information pertaining to V-21MAR-01, B1.324.1 with E484K has been removed as this variant has been reclassified as provisionally extinct. Variants V-21FEB-01 (A.23.1 with E484K), and V-21FEB-02 (Alpha with E484K) are provisionally extinct (not detected for 12 weeks in the UK or in GISAID) therefore are no longer being included in the publication since 12 November 2021. Variant V-21MAY-01, AV.1 has been removed as of 3 December 2021 as it has been classified as provisionally extinct. Variant V-21JUL-01 (Mu) has been removed as of 17 February 2022 as it has been classified as provisionally extinct.   ## UK total distribution for variants with new reports in the last 90 days

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 6 April 2022)
Delta+ V-21APR-02 B.1.617.2 AY.1 AY.2 1,732,446+ +581
V-21OCT-01*** V-21OCT-01 AY.4.2 123,443 +18
Omicron VOC-21NOV-01 B.1.1.529 2,155,763 +7,251
Omicron BA.2 VOC-22JAN-01 B.1.1.529.BA.2 374,445 +28,815

*WHO naming has been included where available.

**Cumulative numbers may be revised up or down as a result of reclassification of results, re-infections and changes to diagnostic tests, new variants or public health management levels.

 ^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 794 had the K417N mutation.

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

UK total distribution for variants detected in the UK with no or low$ activity in the last 90 days

Variant Other names by which this variant may be known* Lineage Total confirmed (sequencing) and probable (genotyping) cases** ^ Last reported specimen date$
Alpha V-20DEC-01 B.1.1.7 281,327*** 5 April 2022
Beta¥ V-20DEC-02 B.1.351 1,064¥ 12 November 2021
Gamma&& V-21JAN-02 P.1 295 17 March 2022
Zeta V-21JAN-01 P.2 50 14 April 2021
Kappa V-21APR-01 B.1.617.1 466 12 April 2022
V-21MAY-02 V-21MAY-02 C.36.3 136 26 June 2021
Lambda V-21JUN-01 C.37 8 18 June 2021

*WHO naming has been included where available.

**Cumulative numbers may be revised up or down as a result of reclassification of results, re-infections and changes to diagnostic tests, new variants or public health management levels.

***A total of 69 historic cases of Alpha (V-20DEC-01) have been added.

 ^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.

$Fewer than 10 reports in any week during the last 90 days.

¥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 23 ‘Beta or Mu’ provisional genotyping cases have been identified.

&&A total of 27 historic cases of Gamma (V-21JAN-02) have been added.

Note on Omicron (VOC-21NOV-01)

As genotyping assays cannot distinguish between BA.1 and BA.2 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 230,399
Northern Ireland 9,360
Scotland 29,124
Wales 12,444
Total cases 281,327

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case with at least 5 V-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).

Beta

Surveillance overview

Total confirmed and probable cases
England 950
Northern Ireland 9
Scotland 62
Wales 43
Total cases 1,064

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case where:
• at least 4 V-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 270
Northern Ireland 0
Scotland 23
Wales 2
Total cases 295

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.

Delta

Surveillance overview

Total confirmed and probable cases
England 1,414,185
Northern Ireland 93,793
Scotland 133,327
Wales 91,141
Total cases 1,732,446

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.

V-21OCT-01

Surveillance overview

Total confirmed and probable cases
England 94,000
Northern Ireland 758
Scotland 13,649
Wales 15,036
Total cases 123,443

Case definitions

Genomic match Criteria
Confirmed
(sequencing)
COVID-19* confirmed case that is confirmed V-21APR-02 with at least 2 V-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.

Omicron

Surveillance overview

Total confirmed and probable cases
England 1,720,180
Northern Ireland 106,553
Scotland 233,099
Wales 95,931
Total cases 2,155,763

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 V-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.

Kappa

Surveillance overview

Total confirmed and probable cases
England 419
Northern Ireland 5
Scotland 27
Wales 15
Total cases 466

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.

V-21MAY-02

Surveillance overview

Total confirmed and probable cases
England 125
Northern Ireland 3
Scotland 4
Wales 4
Total cases 136

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 V-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

Surveillance overview

Total confirmed and probable cases
England 275,008
Northern Ireland 8,359
Scotland 66,930
Wales 24,148
Total cases 374,445

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 polymerase chain reaction (PCR).