Omicron subvariant BA.2 is rising. What do we know about it?

Two years into the COVID-19 pandemic, and just when new cases and hospitalizations in the U.S are on the decline, an Omicron subvariant called BA.2 is gaining significant traction in some parts of the world. Dr. Monica Gandhi, an infectious disease specialist and professor of medicine at the University of California, San Francisco explains what we know about it.

Video transcript

MONICA GANDHI: I would think of it more as a sibling. I think that's a good way to put it. It's kind of like two twins traveling side by side. It's a sub-variant of Omicron, essentially, to BA.1. And it does seem like it's more infectious, at least by a Danish study, which at least in households, 33% more transmissible.

Any time a variant is more transmissible, even if it's a little more transmissible, it seems to have taken on that dominant. So Delta was much more transmissible than Alpha. It took over. Then Omicron, four times more transmissible than Delta. And then if BA.2 is more transmissible than BA.1 it will take over.

Really the question about transmissibility is important. But the most important question that's really come up with all of our variants is does our immunity get evaded? And the simple explanation there, and it's true of all the variants, is that absolutely the antibodies, which are a very important line of defense, can be not as good against Omicron from your vaccine. Which is why we encourage boosters during this time.

The very lucky thing is that it doesn't look like if you got Omicron, the BA.1, that you're not completely protected from BA.2 because they're so close. And also, it was the predominant strain in Asia and then it came over to Europe and the UK, which of course, are a little ahead of us. And it didn't halt their progress. Meaning, cases still were able to go down there, despite BA.2 coming into their regions.

The best way to gotten through Omicron, and I know we didn't have as many booster uptake as in, for example, Denmark. Denmark had a 61% booster uptake. We had lower. But what the point of the booster campaign was to increase our antibodies. When the virus is circulating in high amounts, if we got a booster, it would help raise our antibodies and stave off even mild infections. So getting a booster for BA.1 or BA.2 is an important strategy.