BA.5 May Not Be the Dominant Variant Much Longer. Here's Why and What That Means

This comes as new variants continue to emerge, including the BN.1, which has now been added to the Centers for Disease Control and Prevention's weekly tracker

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The BA.5 omicron subvariant has been the dominant COVID variant in the U.S. for months, but its reign could soon be over.

That's because two descendants of the BA.5 strain could potentially overtake it.

This comes as new variants continue to emerge, including the BN.1, which has now been added to the Centers for Disease Control and Prevention's weekly tracker.

According to the CDC’s “Nowcast,” which shows estimated proportions through Nov. 12, the BQ.1.1 subvariant is now responsible for 24.1% of COVID cases in the United States, while the BQ.1 subvariant is responsible for 20.1% of cases.

Those both represent a significant jump from the previous week, when neither subvariant had yet hit the 20% plateau, according to CDC estimates.

The BA.5 subvariant, which has been the dominant strain of COVID in the United States since early July, dropped from 41.1% of cases to 29.7% this week, signaling that its long-standing reign could finally be nearing an end. In the Midwest, the BA.5 represents 35.3% of cases.

Another COVID subvariant, BN.1, also appeared on the radars this week, making up an estimated 4.3% of cases in the U.S. and 4.2% of cases in the Midwest.

Officials say that the new strain is most prevalent in the western United States, making up more than 6% of cases in an area that includes Arizona, California, Hawaii and Nevada.

The news comes as cases begin to slowly trend upward as northern residents begin to spend more time indoors. According to the latest CDC estimates from Nov. 9, an estimated 288,989 new COVID cases per week are currently being reported in the U.S. That represents an increase of nearly 11% in the last two weeks, according to officials.

In Illinois, cases have largely flattened in recent weeks after an increase in October, but officials remain concerned that cases could rise with more residents spending time indoors and around loved ones during the holiday season.

As of Monday, Illinois was averaging 1,895 new cases of COVID per day.

"When we see a lot of subvariants emerging, we also know that means there is more COVID spread generally," Chicago Department of Public Health Commissioner Dr. Allison Arwady said Tuesday. "Because when COVID spreads, that is when it has the opportunity to mutate, and that's when you see new subvariants emerge."

Arwady noted that hospitalizations related to COVID are on the rise, leading the city to be listed under an elevated community level for the virus, per CDC standards.

The city on Friday climbed from a "low" alert level to a "medium" level, meaning those who are at higher risk of infection should mask in indoor public spaces.

"I would be a lot less concerned if we were tipping into medium because cases were up than if we're tipping into medium because hospitalizations are up," Arwady said.

The new subvariants could also be contributing to potential breakthrough infections surrounding new bivalent booster shots.

"We have seen some breakthrough cases just like we have every time there has been an updated or, you know, since the beginning of COVID," Arwady said. "Yes, it is definitely related to the newer strains, it's good news that we haven't had a new variant of concern... But still, every single one of those new subvariants is outcompeting the old one, meaning it is more infectious, more contagious, and potentially can carry other, you know, other issues with it."

Still, Arwady noted that it is good news all of the subvariants so far are descendants from omicron.

"My biggest worry is if we get a new variant of concern emerging, meaning a variant that is behaving really differently that is genetically very different from omicron, that has more immune escape, that is making more people more seriously ill, especially and even if they're up to date with vaccine, or some other, you know, some other change," she said.

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