The omicron subvariant BA.5 is now responsible for nearly 54% of COVID cases in the U.S., according to the latest data from the Centers for Disease Control and Prevention.
In New England, BA.5 accounts for 41.6% of the region's cases, followed by BA.2.12.1 at 38.1%, BA.4 at 17.8% and BA.2 at 2.5%.
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Dr. Shira Doron of Tufts Medical Center joined NBC10 Boston on Monday to clear up some rumors and misconceptions about the highly-transmissable new strain.
Here's what she had to say:
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Is BA.5 the most transmissable variant yet?
"Not exactly," Doron said. "We continue to see new variants and subvariants become dominant, and there's a misconception that that means each and every one is more contagious than the last. There's even a rumor that BA.5 is as contagious as measles. That's not the case."
"It's becoming dominant because it has a growth advantage over the other variants. It could be it's just evading immunity better, just like flu strains replace each other every year."
If you had omicron already, can you still get BA.5?
"When a variant is immuno-based, it's going to have an easier time infecting you if you've already been infected," Doron said. "Hybrid immunity, though -- immunity from a combination of vaccination and infection -- is pretty powerful. It protects you really well from severe disease. It usually protects pretty well from infection for a while, but not always."
"There are stories of people getting infected in just a month or so after prior infection, but that is definitly not the norm."
Will vaccine boosters work against BA.5?
"Well, BA.5 is omicron, and we know the vaccinations don't do a super great job of preventing infection caused by omicron," Doron said. "But we also know they continue to prevent severe disease, hospitalization and death, and there's no evidence that that fact changes with BA.5. In fact, in South Africa where they have high levels of immunity from vaccination and omicron infection, the BA.5 wave which has ended there was associated with less hospitalization and death than any prior waves."
"Now we know the mRNA vaccine manufacturers are working to make a booster that contains BA.4 and BA.5, but by the time those vaccines are ready for distribution we may have a new circulating subvariant. So only time will tell how successful the fall booster plan will be."
