What is BA.4.6?  Expert explains new COVID variant is now being tracked by CDC

What is BA.4.6? Expert explains new COVID variant is now being tracked by CDC

A new COVID variant is slowly starting to grow in numbers in the US and the Midwest, but how worrying is it and will it overtake the BA.5 variant that currently dominates cases?

According to health experts, much is still unclear about BA.4.6, a descendant of the BA.4 variant that first appeared in April and May. The new strain now accounts for just over 5% of cases nationwide, according to estimates by the Centers for Disease Control and Prevention, up slightly from figures reported a week earlier.

What might be concerning about the variant is a mutation that could allow it to evade immunity, like other omicron subvariants, a Chicago health expert told NBC 5.

“So BA.4.6 is a descendant of omicron BA.4. It does have an extra mutation in the spike protein and as you probably know, this spike protein is what helps the virus get into human cells. So it has also the benefit, because of this mutation in the spike protein, to get additional immune escape…” said Dr. Sharon Welbel, the director of Hospital Epidemiology and Infection Control for Cook County Health. “These newer variants of concern help the virus itself escape natural immunity, or immunity that we have from vaccines, or both.”

In addition to being even more contagious than previous variants, scientists have also tracked a mutation in BA.4 and BA.5 subvariants that could help them evade some immunity and cause reinfections.

That same concern has surfaced with the distribution of BA.4.6.

“It has a specific mutation in the spike protein, and some of the BA.5 lines have had that too, so it’s hard to know if having BA.5 will protect us from BA.4.6. I think that we have to assume it won’t,” Welbel said. “But again… having natural immunity to BA.5 will help protect us from getting seriously ill or dying from it.”

While BA.4.6 will likely soon be the second most common in the US, ahead of BA.4, it remains to be seen if it can top BA.5.

“It looks like it will surpass BA.4. We don’t know if it will surpass BA.5 at this point or where it’s going,” Welbel said. “This particular mutation has been seen in other variants, including some sublines of the BA.5 variant. So at this point I think it’s too early to know, but it looks like it will surpass BA.4.”

There’s good news, as an ommicron-specific booster will be released to the public this fall.

Covid coordinator Dr. Ashish Jha of the White House said on Wednesday that the newly updated COVID-19 boosters will be available to teens and adults “within a few weeks.” The new boosters target the ommicron subvariants BA.4 and BA.5, as well as the original strain of the virus.

The Food and Drug Administration will determine how well the updated shots protect against the virus, Jha said, adding that he expects they “should work much better at preventing infection transmission and serious illness” than the current boosters.

Whether or not it will protect against BA.4.6, however, leaves some room for uncertainty.

“We’ll just have to see,” Welbel said. “Like I said, it’s been found in sublines — the same mutation of BA.5. So the hope is that it will help with other variants, other omicron variants.”

Much remains to be seen about the new variant, including whether it will lead to more serious infections, but Welbel noted that most omicron subvariants are “arguably more transmissible, but significantly less lethal.”

According to Dr. Cyrus Shahpar, White House director of COVID-19 data, the BA.4.6 subvariant has been circulating for several weeks. However, it wasn’t until early August that the variant tracking data started listing the cases of the variant individually.

While the Midwest is seeing cases of the variant that are similar to the national average, with the subvariant accounting for nearly 4% of cases, some neighboring states are seeing rates significantly higher.

For the grouping of Iowa, Missouri, Nebraska and Kansas, CDC data shows the variant accounts for more than 12% of cases as of Tuesday.

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