As Omicron coronavirus outbreak subsides, researchers monitor highly transmissible virus subvariant known as BA.2 . Although it does no...
As Omicron coronavirus outbreak subsides, researchers monitor highly transmissible virus subvariant known as BA.2. Although it does not appear to have the ability to cause a significant new wave of infections, the variant could potentially slow the current decline in Covid cases and make treatment more difficult.
Here’s what we know so far about BA.2.
It’s not really new. Scientists first discovered the Omicron variant in November, and it quickly became apparent that the viral line already existed as three genetically distinct varieties. Each branch of Omicron had its own set of unique mutations. At the time, the most common was the BA.1, which quickly spread across the world. BA.1 was almost entirely responsible for the record spike in cases this winter. At first, BA.1 was a thousand times more common than BA.2. But in early 2022, BA.2 started to be found in a greater proportion of new infections.
It seems to be easier to catch. In Denmark, for example, scientists examined the spread of the two subvariants in households. They found that people infected with BA.2 were much more likely to infect people they shared a house with than those with BA.1.
It is not yet causing a new surge in the United States, and probably will not. Existing vaccines work against the BA.2 variant, and it is vulnerable to antibodies made by the immune system after previous infection with Omicron.
BA.2 does not appear to be more severe than the previous version of Omicron. British researchers have found that BA.2 infection does not lead to a higher risk of hospitalization than BA.1.
BA.2’s “Stealth Variant” moniker is deprecated. BA.2 was dubbed the “stealth variant” when it failed to reveal its presence in positive PCR test samples, making it difficult for researchers to distinguish Omicron cases from those of Delta and D. other variants. BA.2 carried a mutation that hid one of three telltale coronavirus genes that the tests detect. Now that a large majority of positive tests involve Omicron, the missing mutation doesn’t matter: almost all viruses detected by PCR are BA.1, and those that are not are BA.2.
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