New MUSC COVID data show rise of BA.2 subvariant and its offshoot, BA.2.12.1

May 05, 2022
Bar chart shows COVID variants at MUSC. The latest month included, April 2022, shows that all of that month's COVID samples were some form of Omicron.
This bar graph, created by Dr. Julie Hirschhorn, shows the fluctuation in variants over time.

Newly released COVID data from the Medical University of South Carolina show the Omicron subvariant BA.2 and its fast-spreading offshoot, BA.2.12.1, are on the rise.

“BA.2.12.1 is one of the variants that have been in the media. It’s caused a little surge in New York,” said Julie Hirschhorn, Ph.D. She directs the Molecular Pathology Lab at MUSC.

“As a scientist, we love to follow the data. And we don't really have any data to suggest that we're not going to see another surge. So I am preparing as if we are going to see another surge. Hopefully, I am wrong.”

She’s in a good position to keep watch. Her team handles all of the COVID tests that come through MUSC. The ones that come back positive are sequenced — checked to determine their genetic makeup — and categorized by variant.

As you can see on Hirschhorn’s bar chart above in colorful detail, different variants have surged and ebbed over the months. These days, it’s all Omicron. Every subvariant that starts with the letter B is a form of Omicron. Even the little blue bar at the top of April on Hirschhorn’s chart, representing XE, involves a combination of BA.1 and BA.2.

Dr. Julie Hirschhorn talks with Kristen Maurer, a medical technologist who is indexing each coronavirus-positive sample so 384 samples can be sequenced at the same time. 
Dr. Julie Hirschhorn, left, works in a COVID testing lab at MUSC. Photo by Sarah Pack

Omicron has already made a big splash. It caused the biggest surge of the pandemic, peaking in the Charleston area in mid-January. Since then, it has continued to mutate.

Bailey Glen, Ph.D., is a data expert who works with Hirschhorn. “We’re definitely seeing an increase in transmissibility. But the severity question? There's no evidence at the moment that I'm aware of that these subvariants are more severe,” he said.

So what’s ahead? It’s unclear. Three factors to consider:

First, MUSC’s COVID-19 Epidemiology Intelligence Project recently reported an 80% weekly increase in COVID cases in the Charleston area — but the total number of cases remains small.

Second, a hospitalization forecast for South Carolina from the Centers for Disease Control and Prevention predicts a possible increase in the number of people who may end up in the hospital with COVID over the next month. If there is, Hirschhorn said the forecast suggests it’s likely to be a small one.

Third, and more encouraging, a spokesman for the South Carolina Department of Health and Environmental Control said that for now, severe cases are actually on the decline.

Glen hopes that third trend continues. “There is definitely the possibility that it will continue to be less severe, and that's great. Something else that I think is good is that here in the U.S., there’s less of a dramatic change in the genetics as the virus mutates.”

He’s also keeping an eye on two new subvariants that have become dominant in South Africa: BA.4 and BA.5. They’re causing a rise in infections and hospitalizations. That’s the same country where Omicron was first reported last November. In the MUSC data set, which includes samples collected through April 20, there were not any cases of BA.4 or BA.5.

As Glen, Hirschhorn and their colleagues continue to monitor variants, they’re sharing their findings with DHEC. “That way, the epidemiologists across the state have access to that information. What we do is important, but what epidemiologists do is incredibly important because they translate that data into the ways we look at public health efforts and decide what's next, what do we need to do?” Hirschhorn said.

She said MUSC is committed to doing its part. “I think it just goes to show how much MUSC is invested in public health. We have a department devoted to Public Health Sciences and we train students in epidemiology. Obviously, we care for our populations across the state. And I think that it says a lot about the university's desire to ensure that we have the data that we need to move forward, even as we hopefully move toward the tail end of this pandemic. But COVID is not done yet, and it's important to continue to contribute to our knowledge about it.”

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