What are variants of concern?
A “variant” refers to a set of viruses with the same or similar patterns of mutations. Some of these variants are thought to potentially behave differently compared to other virus strains present around the world. Some are thought to be more transmissible (i.e. spread more easily between people), or might cause more severe infection than others - these are labelled as ‘variants of concern’. Data will be gathered in the coming months to confirm whether these variants are significantly more transmissible or cause more severe disease.
Many countries where these variants are not yet present are trying to monitor the COVID-19 infections in their country, and trying to prevent these variants being introduced, or becoming widespread. In Australia and many other countries, genomic sequencing is being used to identify variants of concern (for example, in travellers returning from overseas), so that public health authorities can put measures in place to prevent any spread into the community.
What is a variant of interest?
A ‘variant of interest’ is a further sub-set of the ‘variants of concern’ outlined above, where there is possible evidence that the variant may behave differently compared to the other virus strains that are circulating at present. These have previously been referred to as ‘variants under investigation.
These may or may not be reported to jurisdictional Public Health Units (PHUs) with appropriate exmplanation and liaison with PHUs to interpret their relative significance or otherwise.
What is a variant under monitoring?
A ‘variant under monitoring’ is a another sub-set of the ‘variants of concern’ outlined above, where there are early observations of potential significance that the variant may behave differently compared to the other virus strains that are circulating at present, but little to no evidence of current concern.
Variants under monitoring can be either classified as having potentially having significant impact on clinical or treatment decisions, or may have significant effects on disease transmission.
CDGN VOC Working Group
The CDGN VOC Working Group is responsible for ongoing monitoring and surveillance of SARS-CoV-2 variants literature and global events to inform Australia’s national approach in detecting and reporting of Variants of Concern (VOC), Variants of Interest (VOI) and Variants Under Monitoring (VUM), and mutations of interest reported in the literature. The working group is comprised of laboratory and government representatives with expertise in bioinformatics, genomic epidemiology, viral evolution, phylodynamics and medical microbiology.
The CDGN VOC Working Group meets regularly to review and update the national VOC Laboratory Case Definition and the VOC Literature Summary to ensure the most up to date information is reflected and communicated to the public health laboratories and units. This literature summary is distributed to all jurisdictions across Australia and New Zealand through national committees, the Public Health Laboratory Network (PHLN) and the Communicable Diseases Network of Australia (CDNA). The CDGN VOC Working Group also works closely with the AusTrakka National Analysis Team to ensure timely integration of new VOCs or VOIs that are being monitored and reported in the AusTrakka National VOC reports submitted to the national, state and territory governments on a twice-weekly basis via the Australian Health Protection Principal Committee (AHPPC), PHLN and CDNA.
Current Variants of Concern, Variants of Interest and Variants Under Monitoring
|
Class |
Lineage |
Description |
|
VOC |
Omicron sub-lineages BA*, and associated sub- sub- lineages |
The B.1.1.529 lineage was first reported by South Africa on 24 November 2021, and formally designated a VOC by WHO on 26 November 2021. Omicron has >30 mutations in the spike protein, many of which have been seen in other VOCs. The CDGN VOC WG is closely monitoring this lineage and emerging evidence available to better understand the impact of Omicron’s mutations on transmission, vaccine efficacy and disease severity To date, there are 169,460 sequences identified as B.1.1.529 (Omicron) or recombinant lineage in AusTrakka. |
|
VOI |
XBB.1.5 and sub-lineages |
This recombinant version of the virus was detected in August 2022. It is a result of the swapping of genetic material between BA.2.10.1 and BA.2.75. It has 14 extra mutations in its spike gene compared with BA.2. |
|
VUM |
BA.2.75 (including sub-sub-lineages CH.1.1, BR.2, BN.1) |
Sub-sub lineages and recombinants are classified as VUM because of their potential for resistance to drug therapy, or because there is significant growth in the number of cases which may be of epidemiological significance. |
As of Monday 23 May 2022, the CDGN VoC Working Group has downgraded B.1.617.2 (Delta) to a Variant of Interest. No Delta sequences have been identified from samples collected in the past 12 weeks. Alpha, Beta and Gamma variants were de-escalated from VoCs on Monday 31 January 2022.
Laboratory Case Definitions
Nationally aggregated sample data
The table below shows the total number of Omicron sequences in Australia categorised as variants of concern, variants of interest and variants under monitoring, as well as the number and proportion of sequences identified for each sub-lineage in the past 28 days.
Data is not equivalent to case numbers, as there may be duplicate sequences for a single case, and not all cases have samples which are able to be sequenced. Sequence numbers may vary from week to week as new sub-lineages are characterised and sequences are re-classified into these new sub-lineages.
^ the number (and percentage) of sequences within the preceding 4 week (28 day) period
~ Inclusive of all XBB* sublineages
Green boxes indicate decreases in proportion compared to previous 28-day period, whereas yellow boxes indicate increases in sequence proportion. VOI and VUMs which have not been observed in the past 8 weeks (including XBF, BR.2, BN.1, BF.7, BA.4.6, BQ.1 and BQ.1.1) have been removed from this table.
Global overview
Globally, the number of new cases decrease by 58% during the 28-day period of 8 January to 4 February 2024 as compared to the previous 28-day period, with over 503 000 new cases reported. The number of new deaths decreased by 31% as compared to the previous 28-day period, with over 10 000 new fatalities reported. As of 4 February 2024, over 774 million confirmed cases and more than seven million deaths have been reported globally.
During the period from 8 January to 4 February 2024, COVID-19 new hospitalizations and admissions to an intensive care unit (ICU) both recorded an overall decrease of 32% and 38% with over 114 000 and more than 1300 admissions, respectively.
Globally, JN.1 is the most reported VOI (now reported by 99 countries), accounting for 88.0% of sequences in week 4 of 2024 compared to 64.5% in week 52 of 2023.
This global overview is taken from the latest WHO Coronavirus disease (COVID-19) Epidemiological Update.
Latest COVID-19 news
