Experts play variant guessing game as omicron offshoots dominate

The omicron variant's evolutionary pattern differs from earlier variants and offers hints that the next new strain that emerges may also be in the omicron family, The New York Times reported July 20. 

"None of us has a crystal ball, and we are trying to use every last ounce of what we can from predictive modeling and from the data that we have to try to get ahead of a virus that has been very crafty," Peter Marks, MD, PhD, director of the FDA's Center for Biologics Evaluation and  Research, told the Times

In late June, the agency directed vaccine manufacturers to target omicron sister variants BA.4 and BA.5 — which now account for 90 percent of cases — in updated shots expected to be ready in the fall. Given omicron and its relatives have dominated for about six months, the next version is more likely to be tied to the omicron family than to earlier variants — a key assumption that drove the FDA to select the sister strains as targets for updated shots.  

"It's a near certainty that new mutants will emerge in any given six-month time frame," said Jesse Bloom, PhD, a virologist at Fred Hutchinson Cancer Center in Seattle. "But as long as these mutants are descendants or close relatives of BA.2 or BA.4/BA.5, then a vaccine booster based on BA.4/BA.5, as the FDA has recommended, should be a much better match to them than the current vaccine, even if it's not a perfect match," he told the news outlet. 

Unlike the delta variant, omicron offshoots have outpaced one another. 

"The children of delta were not dominant, but the children of omicron are pushing out their siblings, if you will," said Emma Hodcroft, PhD, an epidemiologist at the University of Bern in Switzerland. "That's hinting that omicron is at the peak and that there will be smaller changes," she told the Times

Still, nothing can be certain about the coronavirus' evolution, and experts say more omicron relatives may not prevent an entirely new variant from appearing. 

"Too many times we have made predictions on how we think SARS-CoV-2 will evolve and then been emphatically wrong," Nathan Grubaugh, PhD, an epidemiologist at the Yale School of Public Health in New Haven, Conn., told the Times


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