How do COVID variants emerge?
Evidence suggests that people with weak immune systems may be accelerating mutations.
Credit: Andriy Onufriyenko / Getty Images
Since its first appearance in Wuhan, China, SARS-CoV2 has been acquiring random mutations. In recent months several new variants have been observed. Some of those cause significant changes in how the virus behaves, including how contagious or deadly it is.
Mutations happen all the time and are entirely random. “It’s just what viruses do,” says Professor Gilda Tachedjian, a virologist at the Burnet Institute and president of the Australian Virology Society.
If we sequenced all the virus particles – virions – from someone infected with SARS-CoV2, we’d find that each particle is slightly different. That’s because when viruses make copies of themselves, they make mistakes. Most of these go completely unnoticed. Others confer advantages to the virus and gradually become predominant.
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