Research and analysis

Variants: distribution of case data, 7 March 2022

Updated 24 June 2022

Surveillance overview

From 31 January 2022, the UKHSA has reported episodes of infection in its coronavirus (COVID-19) surveillance. Current surveillance of COVID-19 in England is 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.

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

Changes to the genomics classification method has led to the reclassification of a small number of historic records this week.

Omicron numbers for Northern Ireland were artificially inflated for the last 4 weeks. This has been corrected in this report and in the preceding 4 reports.

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 23 February 2022)
Delta VOC-21APR-02 B.1.617.2 AY.1 AY.2 1,731,053 +966
Gamma VOC-21JAN-02 P.1 293 +1
VUI-21OCT-01# VUI-21OCT-01 AY.4.2 123,323# +243
Omicron VOC-21NOV-01 B.1.1.529 1,719,716 +75,974
Omicron BA.2 VUI-22JAN-01 B.1.1.529.BA.2 72,133 +34,196

§WHO naming has been included where available.

‡Of which 779 had the K417N mutation.

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.

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 VOC-20DEC-01 B.1.1.7 281,127 31 January 2022
Beta* VOC-20DEC-02 B.1.351 1,064* 12 November 2021
Zeta VUI-21JAN-01 P.2 50 14 April 2021
Kappa VUI-21APR-01 B.1.617.1 465 14 September 2021
VUI-21MAY-02 VUI-21MAY-02 C.36.3 136 26 June 2021
Lambda VUI-21JUN-01 C.37 8 18 June 2021

§WHO naming has been included where available.

$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 21 ‘Beta or Mu’ provisional genotyping cases have been identified.

**Regarding the total confirmed (sequencing) and probable (genotyping) cases, 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. Cumulative numbers may be revised up or down as a result of changes to diagnostic tests, new variants or public health management levels.

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 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 230,394 ¥
Northern Ireland 9,162
Scotland 29,127
Wales 12,444
Total cases 281,127

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 25 February 2022).

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 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 268
Northern Ireland 0
Scotland 23
Wales 2
Total cases 293

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 1,413,104
Northern Ireland 93,276
Scotland 133,568
Wales 91,105
Total cases 1,731,053

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.

VUI-21OCT-01

Surveillance overview

Total confirmed and probable cases
England 93,926
Northern Ireland 745
Scotland 13,633
Wales 15,019
Total cases 123,323

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.

Omicron

Surveillance overview

Total confirmed and probable cases
England 1,408,527
Northern Ireland 85,381
Scotland 142,046
Wales 83,762
Total cases 1,719,716

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.

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-21MAY-02

Surveillance overview

Total confirmed and probable cases
England 126 ¥
Northern Ireland 2
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.
¥ 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 25 February 2022).

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 60,357
Northern Ireland 3,027
Scotland 5,664
Wales 2,779
Total cases 71,827

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.