“One of the theories is that the strain developed in an immuno-compromised person who harbored the virus for much longer than normal, allowing it to go through many adaptations.
In southern Africa, the high rate of HIV infections means that millions of people have a weakened immune system. While most are on antiretroviral drugs that prevent the HIV virus from multiplying, many aren’t. That means that their ability to fight off and rid the body of pathogens is severely diminished. Advanced cancer sufferers have similar immune system problems.”
Source: Bloomberg
By Janice KewDecember 10, 2021, 7:20 AM EST
Seeking answers on omicron
Omicron’s sheer number of mutations has raised many questions—including whether the variant will evade vaccines, spread more easily and lead to severe illness. The strain’s changes are also causing scientists to puzzle over its origins.
When the scientist who first detected the new variant in late November took samples from foreign diplomats who had traveled together to Botswana and sequenced them, the international database provided a surprise: The samples most closely resembled a strain first detected in early April 2020 and known as the U.A.E lineage.
After Sikhulile Moyo, director for the Botswana Harvard HIV Reference Laboratory and a research fellow at Harvard T.H. Chan School of Public Health, looked more closely, he saw the earlier variant had fewer mutations and ruled out what he was seeing as being the same.
What it did show was that omicron has an unusually large number of mutations on the gene that helps the coronavirus spread. Since omicron’s discovery, others have checked samples sitting in freezers in their laboratories and found that the lineage was already circulating as early as October.
Viruses don’t accumulate mutations in a single step. So scientists are still trying to understand how so many mutations arose for omicron in an apparently short space of time.
One of the theories is that the strain developed in an immuno-compromised person who harbored the virus for much longer than normal, allowing it to go through many adaptations.
In southern Africa, the high rate of HIV infections means that millions of people have a weakened immune system. While most are on antiretroviral drugs that prevent the HIV virus from multiplying, many aren’t. That means that their ability to fight off and rid the body of pathogens is severely diminished. Advanced cancer sufferers have similar immune system problems.
Another hypothesis being looked into is whether the variant could have been transferred from people into an animal host, where it adapted to that host relatively quickly and then moved back into humans.
It could also be that there simply hasn’t been enough global testing of various Covid samples and that close relatives of omicron had already developed undetected.
Trying to figure out omicron’s origins is important as it gives insight into how it’s behaving and what SARS-CoV-2, the coronavirus that causes Covid-19, might do next.
Still, figuring out the origins of a virus is often tricky, and the contentious issue of how the virus that sparked the pandemic first appeared in people hasn’t yet been answered.—Janice Kew
Martin Plaut 