Nehe City Media Center
Recently, a new variant of the Omicron strain numbered "BA.2.75" has attracted great attention from scientists in Israel and other countries. This variant evolved from the BA.2 variant of the Omicron strain and is called the "second generation variant" of . It has many "unusual" mutations and may be able to break through existing vaccines and strain infection constructs. There is no effective immune barrier and the infection speed is relatively fast. Cases have appeared in India, Japan, the United States and other countries. Experts related to are worried that this variant can replace existing variants such as BA.2 and BA.4, setting off a new epidemic peak in the world.
New mutation mutation causes concern
As of July 2, researchers from various countries have discovered 85 genetic sequences of the BA.2.75 variant in international new coronavirus genome databases such as "GISAID". This variant first appeared in early June. The gene sequence from India quickly appeared in seven other countries, including the United Kingdom, the United States, Japan, Canada, Australia, New Zealand, and Germany. Since the number of new coronavirus genomes shared by various countries is only the "tip of the iceberg" of the global number of new coronavirus cases, the actual number of people infected with the BA.2.75 variant is far more than 85.
Source: Visual China
Dr. Shea Friesen, an expert at the Central Virology Laboratory of the Israeli Ministry of Health, said on social media platforms that the emergence of BA.2.75 is "worrying" and that it evolved from the BA.2 variant. "The second generation variant" has 16 new mutations compared to BA.2, 8 of which are located in the spike protein gene region.
The American Bloom Laboratory stated on the social media platform that compared with its BA.2, this variant has two key mutations, G446S and R493Q, of which G446S will lead to changes in the characteristics of the antigen , helping the virus to break through existing vaccines and other constructs The immune barrier, R493Q improves the ability of the virus to enter human cells, so BA.2.75 is worthy of further tracking.
British virology expert Tom Peacock said that BA.2.75 has a large number of spike protein mutations and is a "second-generation variant" of . It spreads quickly and has a wide geographical distribution, so it requires close attention.
BA.2.75 may become the first successful "second-generation variant"
According to the explanations of Shay Friesen, Tom Peacock and others, the so-called "second-generation variant" refers to the "first-generation variant" A variant that has evolved, but has more mutations and is significantly different from the first-generation variant. For the Omicron strain, variants such as BA.1, BA.2, BA.3, BA.4, and BA.5 are "first-generation variants", and BA.2.75 may become the first. A successful "second generation variant".
Shay Fryson said that before BA.2.75, researchers had discovered many "second-generation variants" of the new coronavirus - "these samples can be found every day", but previously discovered variants have not been able to It spreads widely and has a small sample size, while BA.2.75 has spread in many different countries and has dozens of sample sizes, and it seems to be successful. BA.2.75 is only the first "successful plan" and represents the "next step" in the evolution of the Omicron strain (that is, the generation of more "second-generation variants"). More complex genetic changes may occur in the future.
Tom Peacock said that the "second generation variants" evolved from existing and successful variants. These variants already have "nasty " antigenicity, transmissibility, etc. traits, which could mean they are more susceptible to acquiring more threatening combinations of mutations.
New epidemics may arise in the future
Studies have shown that the BA.2 variant of the Omicron strain is more contagious than the BA.1 variant that appeared earlier. At the end of last year, after the emergence of the Omicron strain, the BA.1 variant first set off an unprecedented peak of epidemics around the world; in March and April this year, BA.2 gradually "replaced" BA.1, causing the epidemic in the United States, Europe, etc. China entered another round of the epidemic; after June, the spread of BA.4 and BA.5 variants intensified the epidemic again in Europe, Israel and other places.
Many experts believe that BA.2.75 is likely to have a competitive advantage compared to other variants.
Australian data processing expert Mike Honey believes that BA.2.75 spreads extremely fast. Between June 15 and 30, the proportion of this variant in genome samples uploaded by India rapidly increased from less than 5% to 18%. shows that it is replacing other variants of , and its spread speed seems to be faster than that of BA.2 and BA.5 variants of .
Raj Rajnarayanan, associate professor of biology at the New York Institute of Technology, also believes that BA.2.75 may replace BA.5, BA.4 and other BA.2 variants that are spreading. There is currently too little data to draw conclusions. Reliable results, with growth advantages likely to become apparent within weeks.
Tom Winslers, a professor of biology at the University of Leuven in Belgium, also said that he is very sure that the growth advantage of BA.2.75 over BA.5 is real.
Ulrich Elling, a researcher at the Institute of Molecular Biotechnology of the Austrian Academy of Sciences, said that before we get through the BA.5 wave, we may have already prepared for the next wave. BA.2.75 and BA.5 are in the spike protein. There are 11 mutations in the gene region. The immune barrier produced by BA.5 infection is likely to be unable to protect against BA.2.75, leading to a new infection peak.
Source: Hecheng release
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