Will the Gryphon subvariant replace Omicron?
In the United States XBB, known as Gryphon, has increased by 140% in the last month and in Italy the ISS has found a 'significant increase'. Is this the subvariant found in the positive passengers from China who arrived in Milan? All the details
Is Gryphon the new variant that is sweeping China and could replace Omicron worldwide?
The abolition of almost all the restrictive measures linked to the zero Covid policy and the surge in cases, due to the few vaccinations and relatively effective vaccines, combined with the possibility of traveling could be an explosive mix for a new wave of infections not only in China , where it is already underway , but also in the rest of the world.
But what particularly worries experts is that the XBB subvariant of the Sars-CoV-2 virus, also known as Gryphon, could take over and become dominant because it is able to evade both immunity derived from vaccines and from infection.
Meanwhile, many countries, including Italy, Japan, Malaysia, Taiwan and India have imposed the swab for those arriving from China, the United States is also asking those coming from Macao and Hong Kong who, aligning themselves with Beijing's indications, are equally eliminating most of the restrictions for visitors who will no longer be asked to undergo a swab from today.
Yesterday, however, almost one in two passengers who landed at Milan Malpensa from China tested positive for Covid. Reason why the Minister of Health, Orazio Schillaci, has ordered mandatory swabs and the sequencing of the virus, essential to identify any variants.
WHAT WE KNOW ABOUT GRYPHON
Gryphon, name attributed by the media to the XBB subvariant is the 'daughter' of the recombination of two other Omicron subvariants: BA.2.10.1 and BA.2.75.
In the XBB subvariant mutations were detected not only on the Spike protein, but also four on the N nucleoprotein, which has the function of protecting the viral genome, and five on the enzyme necessary for the virus to reproduce its genetic material.
According to experts, it is responsible for the high number of infections in China, where it has been circulating since October.
WHY WORRY
"A real swarm of variants is circulating, some of which would represent a convergent evolution, first of all XBB, which is rapidly replacing common subvariants, such as BQ.1 and BQ.1.1," said virologist Francesco Broccolo. of the University of Salento.
“To make it advance so quickly – he explained – would be a mutation, called F486P, which would allow it to escape the antibodies generated both by Omicron 5 infections and by vaccines, including the bivalent mRNA vaccine. It would also strengthen the link with the ACE2 receptor, i.e. the entry gate of the virus, present above all on the cells of the respiratory epithelium".
In addition to concern about the spread of Gryphon, Walter Ricciardi, professor of hygiene at the Catholic University, recalled that millions of infections open up the possibility of a new, more pathogenic variant emerging. Meanwhile, the response on which variant was found in the positive passengers who arrived in Milan yesterday is expected today.
WHAT'S WRONG
For Broccolo, however, neither the abandonment of the restrictions nor the lower efficacy of non-mRNA vaccines would be enough to justify what is happening in China: "Something very important is happening, the number of deaths from Covid is uncontrollable and so far only hinted at the possibility that one or more new variants may circulate”.
Another aspect that does not add up was highlighted by the geneticist Massimo Zollo, coordinator of the Covid-19 Task Force of the Ceinge of Naples, who reported that the genetic sequences deposited by China in the Gisaid international bank, updated as of December 22, indicate that " above all the subvariant BA.5.2 and BF.7 are in circulation and that there are 81 sequences of the subvariant XBB filed as of 9 December”. This, according to the expert, indicates "that the Sars-CoV-2 virus is improving in its ability to replicate" but also that the sequencing of the variants has been interrupted or has not been made public.
THE DIFFUSION OF XBB IN THE WORLD
Although for now it is a hypothesis, Gryphon would also seem to be linked to the increase in cases recorded in the United States. In New York, in particular, it has increased by 140% in the last month, recording a hospitalization rate higher than that seen with the Delta variant.
According to Our World in Data, which cites data deriving from genetic sequences deposited in the Gisaid database, XBB has already rapidly spread to at least ten countries, six of which are European: United Kingdom, Belgium, Spain, Germany, France, Italy, United States , Australia and Canada.
THE MOST WIDESPREAD VARIANTS IN ITALY
In Italy, if in the flash survey of the Higher Institute of Health (ISS) of 18 November XBB.1 (recombinant omicron/omicron) was equal to 2.4% of cases, in the last update of 23 December XBB (recombinant of the sub -omicron lineages BJ.1 and BM.1.1.1) is reported as 'highly transmissible and with mutations associated with immune evasion'.
However, according to the ISS, Omicron 5 still remains largely predominant, with a national prevalence of 90.6%. However, we note a 'significant increase' of 64.1% (vs 30.7% in the previous survey) of BQ.1, known as Cerberus.
This is a machine translation from Italian language of a post published on Start Magazine at the URL https://www.startmag.it/sanita/la-sottovariante-gryphon-sostituira-omicron/ on Thu, 29 Dec 2022 10:13:27 +0000.