ECDC has announced that it has delisted Omicron 2, 4 and 5 variants of concern, which dominated throughout 2022. The COVID-19 pandemic now in Europe is led by Kraken and Cerberus.
Particles of the coronavirus on human cells. Credit: NIAID
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The European Center for Disease Prevention and Control (ECDC) announced that as of today, Friday March 3, 2023, it has deleted Omicron BA.2, BA.4 e BA.5 – known respectively as Omicron 2, 4 e 5 – from your list of variants of concern (VOC) del coronavirus SARS-CoV-2. The reason is simple: they no longer circulate in the territory of European countries. Emerging in early 2022 along with other daughter variants of Omicron, first discovered in South Africa in late 2021, these stumps have been responsible for numerous waves of infections throughout the last year, but in recent months they have been supplanted by other lineages that have become dominantalways derived from the original Omicron.
That this variant of concern (the fifth since the beginning of the pandemic of COVID-19 after Alpha, Beta, Delta and Gamma) would have created big problems, this had been intuited since its discovery in the African state, due to the very high and anomalous number of mutations present on protein S o Spike. This is the “biological lock” exploited by the SARS-CoV-2 coronavirus to bind to human cells through the ACE-2 receptor, break the cell wall and insert the viral RNA inside, starting the infection / replication process. basis of the disease, called COVID-19. The “super mutated” Omicron variant has thus spread rapidly throughout the world and has given rise to a multitude of daughter strains that have entered into competition with each other, which in turn have continued – and still continue – to generate further subvariants, even of type recombinant like the notorious ones XBB Gryphon e XBB 1.5 Crack.
This internal struggle between the different daughters of Omicron has always favored the more transmissible and with the best immunoevasive advantageor the ability to evade the neutralizing antibodies (both those induced by vaccination and by a previous natural infection). The competition left several “victims” on the field, now including BA.2, BA.4 and BA.5. But their removal from the list of variants of concern does not mean that the pandemic is over or that SARS-CoV-2 cannot give rise to further blows, with new variants that are even more transmissible and elusive.
Today, in this list, they appear only variants of interest (YOU) e variants under monitoring (VUM), a situation that “reflects the current stable epidemiological situation in the EU/EEA”, specifies the ECDC. However, the European health agency adds that this “does not mark the end of the threat posed by SARS-CoV-2 and the possible future variants that could emerge”. Simply put, we are still experiencing a pandemic and we absolutely must not let our guard down. As regards the variants of interest, among them are: BQ.1 this”Cerberus” (descendant of Omicron 5); BA.2.75 (descendant of Omicron 2); XBB “Gryphon” (recombinant between BA.2.10.1 and BA.2.75); and XBB 1.5 “Kraken” (recombinant between BA.2.10.1 and BA.2.75), which was recently added. The VUMs include BF.7 (descended from Omicron 5); BA.2.3.20 (descendant of Omicron 2); CH.1.1 (derived from BA.2.75); BN.1 (derived from BA.2.75); XBC and XAY.
As regards the incidence of the variants dominated in Europe, theECDC latest bulletin (relating to swabs sequenced between February 6 and 19) indicates that the prevalent one is Kraken, with an incidence of 33.8 percent. Followed by Cerberus al 26.8 percent; BA.2.75 al 22.2 percent; BA.5 to 7 percent; Gryphon at 5.7 percent; BA.2 at 1.2 percent; and BA.4 at 0.3 percent. The three deleted sub-variants are still present in this list, but in a very low percentage compared to the first in the class and in constant decline, week after week. For this they have been deleted from the list of variants of concern.