DENVER — Colorado health officials confirmed the state's first case of a subvariant originating from the COVID-19 omicron variant.
The Colorado Department of Public Health and Environment (CDPHE) said the BA.2 case was identified in late December through genetic sequencing of clinical samples submitted to the state lab.
CDPHE said it appears the original omicron variant (BA.1) is being replaced in some countries by BA.2 cases. That suggests it may have an advantage over BA.1, such as increased transmissibility.
However, CDPHE said there is no evidence at this time suggesting BA.2 causes more severe illness in patients or is more capable of evading immunity.
"I think the question is – does it change anything or is it just another one out there?" said Dr. Michelle Barron, senior medical director of infection prevention and control for UCHealth.
"I don’t want people to be alarmed, but they should be informed," Barron said.
Some have referred to this subvariant as a "stealth variant," a moniker that sounds more dramatic than Barron's explanation of how it got that description.
"With this one, I don’t know if there's any clinical differences they’ve recognized so far. It's only because they’re doing this molecular sequencing and looking at every single virus that they even picked up on it," she said.
"I think that’s why there's interest, and why it's 'stealth,' because nobody would have picked up on it because the clinical outward effects on it are the same as omicron," she said.
Scientists have been tracking multiple variants and subvariants since the pandemic started. Some make headlines, while others don't, Barron said.
To understand variants, she uses a simple analogy.
"We have the original strain, or the ancestral version, and then we’ve had all the variants," she said. "And the variants [are like] siblings, in that they look very similar to the parents, or they could be a cousin."
So how is a subvariant different than a whole new variant?
"Think of a subvariant as almost like a fraternal twin," she said. "They share a lot of the same genetics, and they’re there at the same time and they look maybe very similar, but they’re not [exactly] similar."
"There is more in common than there is not," she said.
CDPHE is monitoring wastewater for the new subvariant. Right now, it has not detected "a constellation of mutations consistent with the presence of BA.2."
"The best protection against COVID-19 and its variants to get vaccinated," CDPHE said in a statement. "We urge all adult Coloradans and all parents and guardians of children 5-17 to make a vaccine appointment, and for those 12 and up, to get a third dose when it is time."
There is reason, beyond just research, that scientists track the development of COVID variants.
"To just understand the scientific evolution of these viruses and give us some idea of where to navigate, and how to respond," Barron said. "Because we can say, 'Ooh, these mutations continue to happen. We should develop drugs to make sure to capture that. Or, our future vaccines need to make sure we have this component.'"
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