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Omicron 101: The how, what and why of the latest super variant

Experts say latest form of COVID-19 shows a virus can play "the long game" by getting milder, but in some countries only.

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ROCHESTER — Much is yet to be learned about the latest COVID-19 super variant.

The omicron variant of SARS-CoV-2 could have developed due to the lop-sided waning of some, but not all, antibodies in a human host.

Or omicron could have mutated after the combining of SARS-CoV-2 with another coronavirus following a lengthy stay in the body of a host, possibly an immunocompromised person.

Or omicron could have become viable within wildlife who got COVID-19 from us, changed it, then gave it back in a different form.

Omicron could signal a "long-game" evolutionary plan for COVID-19, one in which it becomes ever-present but milder.

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That said, omicron could end up causing serious illness in Americans in spite of its milder presentation in African countries.

Those are just a few of the observations now in play on the new super variant of COVID-19 first identified last month in South Africa, and which has now been detected in 19 U.S. states and 50 countries, an undercount to be sure.

"It's in every state, or soon will be in every state," Mayo Clinic infectious disease expert Dr. Gregory Poland said of the omicron variant during a news conference Wednesday, Dec. 8. "The reason for that is exponentiality."

With omicron having more than 26 mutations on the spike protein used for transmission, Poland says the variant of concern is two to six times more transmissible than the highly transmissible delta variant, which had just 10 mutations on the same region of the virus.

A virus from humans to wildlife?

The genetic distance between omicron and other variants of concern is large, signaling the new strain could have derived from more than just the normal path via errant duplication in a human host.

The three leading theories as to how this happened include selective pressure, viral recombination and reverse zoonosis. A selective pressure pathway is one in which omicron would have been created when some, but not all, of a human host's immunity had waned.

"You become partially susceptible, and what the virus most wants to do is to continue to infect," Poland said. "So it will learn how to mutate around existing immunity."

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Dr. Greg Poland
Dr. Gregory Poland, Mayo Clinic physician. Contributed / Mayo Clinic

A viral recombination origin story to omicron, on the other hand, "means somebody was co-infected with two or more coronaviruses, and those coronaviruses exchanged large pieces of genetic material," Poland said.

"With prolonged active infection, someone who is immunocompromised could play a likely host for viral recombination," he said. This could explain "why we got such a different-looking virus."

Finally, it's possible that omicron is unique because it was built inside of an animal species that contracted SARS-CoV-2 from a human, then played host to extensive mutations while unbothered by treatments, masks or vaccination, then passed it back to a human.

The deer population is one likely reservoir for mutations such as these, Poland said, having shown a high prevalence of antibodies for COVID-19 throughout the state of Iowa according to a recent widely reported study.

Less severe omicron not necessarily in store for U.S.

Omicron is described in preliminary observations as more transmissible than delta, but less capable of sending infected persons to the hospital. Poland says Darwinian selection rewards such mutations, in the way in which they preserve hosts to enable greater spread.

"It fits with the long game of the virus," he said.

"From the viral point of view, the perfect scenario is something akin to influenza, which is a virus that mutates toward being very transmissible, but not so virulent that you're in bed. Because if you're in bed, you're not going to transmit the virus."

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Could mutation toward less virulence signal that omicron represents a COVID-19 on the path toward becoming a common cold?

"Absolutely," he said.

But, Poland cautioned, the mildness of omicron in Africa is no guarantee of how it will affect populations raised in the West.

"For reasons that are not entirely clear even with delta," he said, "Africa has not had the same level of death rate and severe illness that the U.S. has had ... What seems to be less severe disease in Africa with omicron, may not be true in high-income urban centers."

The one known fact about omicron is that COVID-19 is here to stay, and will exist in some form going forward.

"This will continue to happen," Poland said of transmission in the absence of adherence to mitigation and vaccination.

"It is impossible for it to not happen, given that much of the US has decided to act as if the pandemic is over ... We can no longer eradicate this virus and this disease. Your great-great-great grandchildren will be getting immunized against this disease."

Paul John Scott is the health correspondent for NewsMD and the Forum News Service. He is a novelist and was an award winning magazine journalist for 15 years prior to joining the FNS in 2019.
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