Nämä kuusi VOC-LUM linjaa ovat Kiertävien VOC-varianttien alalinjoja, joissa on huomattu olevan joitain kasvuetupiirteitä ja omia mutaatioitkin.
Ne ovat ensinnäkin BA.1 -ja BA.2 -linjojen sisarlinjat BA.4 ja BA.5 .
Sitten muut ovatkin BA.2 alalinjoja ja niistä seuraavat: BA.2.9.1, sitten BA.2.11 ja BA.2.12.1 sekä BA.2.13.
Sitaatti:
VOC lineages under monitoring (VOC-LUM)
Latest VOCs have largely replaced other co-circulating SARS-CoV-2 variants. Delta reached almost 90% of all viral sequences submitted on GISAID by October 2021, and Omicron is currently the dominant variant circulating globally, accounting for >98% of viral sequences shared on GISAID after February 2022. As transmission of these VOCs has been sustained, this has led to significant intra-VOC evolution. Since its designation as a VOC by WHO on 26 November 2021, viruses part of the Omicron complex have continued to evolve, leading to descendent lineages with different genetic constellations of mutations. Each constellation may or may not differ in the public health risk it poses, and each lineage that includes substitutions in key sites may need further investigation to assess whether its characteristics diverge or not from those that define the variant of concern they stem from.
In light of the widespread transmission of the Omicron VOC across the globe and the subsequent expected increased viral diversity, WHO has added a new category to its variant tracking system, termed “VOC lineages under monitoring” (VOC-LUM) to signal to public health authorities globally, which VOC lineages may require prioritized attention and monitoring. The main objective of this category is to investigate if these lineages may pose an additional threat to global public health as compared to other circulating viruses. If any of these lineages is proven to have distinct characteristics as compared to the original VOC it belongs to, the TAG-VE will convene and may advice WHO to give it a separate WHO label.
Working definition:
A variant that, according to phylogenetic analysis, belongs to a currently circulating VOC
AND
shows signals of transmission advantage compared to other circulating VOC lineages
AND
has additional amino acid changes that are known or suspected to confer the observed change in epidemiology and fitness advantage as compared to other circulating variants.
VOC-LUMs*:
| Pango lineage | GISAID clade | Nextstrain clade | Relationship to circulating VOC lineages | Genetic features | Earliest documented samples |
|---|---|---|---|---|---|
| BA.4# | GRA22A | 22A | BA.1 and BA.2 sister lineage | BA.2-like constellation in the spike protein + S:del69/70, S:L452R, S:F486V, S:Q493 reversion | South Africa, Jan-2022 |
BA.5# | GRA | 22B | BA.1 and BA.2 sister lineage | BA.2-like constellation in the spike protein + S:del69/70, S:L452R, S:F486V, S:Q493 reversion | South Africa, Jan-2022 |
BA.2.12.1 | GRA | 22C | BA.2 sublineage | BA.2 + S:L452Q, S:S704F | United States of America, Dec-2021 |
BA.2.9.1§ | GRA | - | BA.2 sublineage | BA.2 + S;L452M | Multiple countries, Feb-2022 |
BA.2.11** | GRA | - | BA.2 sublineage | BA.2 + S:L452R | Multiple countries, Mar-2022 |
BA.2.13§ | GRA | - | BA.2 sublineage | BA.2 + S:L452M | Multiple countries, Feb-2022 |
*VOC-LUMs are tracked under Omicron unless/until sufficient evidence arises that the virus characteristics are substantially different from what is known about the VOC they belong to. If this evidence arises, WHO will decide, in consultation with the TAG-VE, if designation of the emerging variant warrants a separate WHO label.
# these lineages have identical constellation of mutations in the spike and the following differences outside the spike: BA.4: ORF7b:L11F, N:P151S; BA.5: M:D3N. Both have reversions at nsp4: L438 and ORF6:D61
§these lineages have identical constellation of mutations in the spike and the following differences outside the spike: BA.2.9.1: ORF3a:H78Y, N: P67S, N: S412I
**additional mutation outside the spike protein: ORF1a:S2519P
