Russia (bbabo.net), - A modified version of the omicron, called BA.2, has spread rapidly in countries such as Denmark, the Philippines and South Africa over the past few weeks, replacing its predecessor, BA.1, everywhere. Early laboratory studies have shown that Omicron-2 is even more contagious than Omicron and appears to bypass vaccine immunity just as easily. In the weekly review of Nature, experts from around the world try to assess the threat from the coronavirus that continues to mutate.
"A laboratory study of BA.2 has shown that its rapid spread is likely the result of being more contagious than BA.1. Other preliminary studies indicate that BA.2 can easily overcome immunity from vaccination or previous infection associated with earlier variants of the coronavirus," says Nature.
Even if real-world epidemiological studies confirm these findings from laboratory experiments, scientists nevertheless suggest that Omicron-2 is unlikely to cause a second equally large wave of infections, hospitalizations and deaths after the initial onslaught of Omicron. But the high incidence may be delayed.
"This could prolong the wave of high infections caused by the omicron. But our data suggest that this will not lead to an entirely new additional surge," said Dan Barush, an immunologist and virologist at the Boston Medical Center. Dr. Barush led the lab study published on the medRxiv preprint resource.
The steady increase in the prevalence of BA.2 in many countries indicates that this variant has advantages over other circulating variants, Mads Albertsen, a bioinformatics specialist at the University of Aalborg in Denmark, quoted the publication as saying. The expert also notes that in addition to Omicron-2, further strains have already been isolated, in particular, the BA.3 line, which is less common today.
The researchers believe that the main reason omicron quickly supplanted the delta variant is because of its ability to infect and spread to people who were already immune to the delta. Hence, it can be concluded that the increase in the spread of BA.2 can also be associated with the fact that it is better than BA.1 in overcoming the immune protection received from BA.1 infection.
The two "omicrons" cannot be called "siblings" - the different behavior of these variants can be explained by their numerous genetic differences. "Dozens of mutations separate BA.1 from BA.2 - especially in key parts of the virus spike protein, the target of powerful antibodies that can block infection. BA.2 has a whole host of new mutations that no one has yet tested," says Jeremy Luban, a virologist at the University of Massachusetts School of Medicine.
To evaluate how vaccination protects against BA.1 and BA.2 infection, scientists conducted laboratory experiments with the blood serum of people who received three doses of the Pfizer vaccine - they assessed how well the "neutralizing", that is, virus-blocking antibodies in the blood of vaccinated people protect cells from virus infection. In addition, the blood of volunteers who received immunity in a natural way - having been ill with "omicron" was examined. In both groups, antibodies performed better against BA.1 (protecting against re-infection) and slightly worse against BA.2.
Therefore, the risk of BA.2 spreading and crowding out BA.1 remains. Anyway, researchers in Israel have identified several cases where people who recovered from BA.1 became infected with BA.2. And now researchers are trying to understand how often such re-infections occur, and what it could threaten on a global scale. Troels Lillebaek, a molecular epidemiologist at the State Serum Institute in Copenhagen and chairman of the SARS-CoV-2 Variants Risk Assessment Committee in Denmark, said this. The scientist assumes that both vaccinations (including the booster one) and the transferred infection will still protect against the coronavirus that continues to mutate, including both Omicron-2, but what level of this protection will be is not clear. "We'll know for sure in a few weeks," Dr. Lillebeck was quoted as saying by Nature.
In Denmark, where vaccination rates are high, the rise in BA.2 prevalence is not yet a major problem, Lillebaek notes. Preliminary research has shown that this variant does not appear to cause more severe disease than BA.1, including in children.
However, according to the scientist, BA.2 may create more serious problems in places with lower vaccination rates. “I think the main problem with BA.2 is its even greater contagiousness, that is, the ability to spread in the human population,” said Lillebeck. “There is a risk that even more people will test positive in a short time, which will create a burden on the hospital system".In addition, there are indications that BA.2 may be resistant to monoclonal antibody therapy. However, drug manufacturers claim that the first laboratory experiments confirm that have been successfully used to treat previous strains remain effective against Omicron-2 (BA.2). in particular to one called sotrovimab, which was effective against BA.1. However, the manufacturer of the drug, Vir Biotechnology in San Francisco, California, said in a Feb. 9 press release that its own unpublished experiments show that sotrovimab remains effective against BA.2.
In general, scientists acknowledge that the coronavirus remains a “puzzle” in many ways, changes and behaves unpredictably, and therefore leaves a wide field for research.
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