The surprising number of mutations in the Omicron coronavirus variant could signal that it originated in a patient with HIV or another immunodeficiency, a top German immunology expert said.
Carsten Watzl, secretary general of the German Society for Immunology, said it was not only conceivable but also probable, and cited similar findings that have been published in other cases.
The virus can replicate over many weeks in people with weakened immune systems, Watzl said.
"During this process, there can be repeated isolated mutations which may not give the virus any advantage, but could nevertheless continue to multiply due to the immune system's failure to control them," he said.
He said this could lead to additional mutations, which in combination could be an advantage for the virus.
Compared to the original strain of coronavirus which first surfaced in Wuhan, China, Omicron has an unusually high number of about 30 amino acid changes in the spike protein alone.
Some of the mutations are known to be associated with greater transmissibility and immune evasion, but Watzl said it is still not clear what effect this particular combination of mutations will have.
Many HIV patients in Africa do not receive adequate treatment, which is why their systems are significantly weakened, Watzl said.
To prevent the spread of variants as extensively mutated as Omicron, it would be important to identify infected immunocompromised people and isolate them until they are no longer infectious, he said.
"Because even if the virus mutates severely in a person, it is the passing on of the mutated virus that is really dangerous," he said.