Yes, Omicron Is Loosening Its Hold. But the Pandemic Has Not Ended.

The lack of widespread vaccination, in the United States and worldwide, coupled with the uncertainty regarding the strength of immunity left behind by Omicron, opens the door to the possibility of new variants. Someday, one of them may dodge immune defenses as well as, or even better than, Omicron does.

“I consider Omicron an example of what endemic Covid-19 looks like,” said Kristian Andersen, a virologist at the Scripps Research Institute in San Diego. “But this doesn’t end with Omicron, because future variants will emerge.”

Neither vaccines nor infections offer so-called sterilizing immunity, meaning that the protection they offer appears to weaken over time. The protection gained from a Delta or Omicron infection may not be as effective against new variants, as the virus is changing unexpectedly quickly and in unusual ways.

Viruses typically evolve in a ladderlike pattern, with each new variant developing from the one before it. But the three riskiest variants of the coronavirus — Alpha, Delta and Omicron — evolved independently. The coronavirus wasn’t building on previous work, so to speak — it repeatedly reinvented itself.

As more and more of the world is vaccinated, evolution will favor forms of the coronavirus that can sidestep antibodies and other immune defenses.

“We could get another variant kind of out of the blue that’s responding to a selection pressure that we hadn’t really thought about, or with mutations that we didn’t really put together,” said Emma Hodcroft, a molecular epidemiologist at the University of Bern in Switzerland.

Article source: https://www.nytimes.com/2022/01/27/health/omicron-covid-pandemic.html