MUSC lab detects BA.4 and BA.5 subvariants

June 13, 2022
Blue, orange and red bar chart showing the ascent of Omicron subvariants.
MUSC’s molecular pathology team has been sequencing COVID samples since January 2021 to see what strains are showing up. All of the subvariants that start with a B are offspring of the Omicron variant, including BA.4 and BA.5.

Scientists at the Medical University of South Carolina have detected the Omicron subvariants BA.4 and BA.5 in their latest sequencing run. Sequencing involves looking at the genetic makeup of COVID samples.

“We had one of each. The BA.4 was from the Lowcountry and the BA.5 was from the Upstate,” said Bailey Glen, Ph.D. He’s a scientist who specializes in using computer data to analyze biological data, and an assistant professor in the College of Medicine.

The two cases were among 60 included in the sequencing run. All of the COVID-positive samples came from people who got tested at MUSC sites.

This marks the first time BA.4 and BA.5 have shown up in the MUSC sequencing data, but it’s not likely to be the last. The Centers for Disease Control and Prevention recently estimated that BA.4 and BA.5 represented 13% of all new cases in the U.S., up from about 7% a week ago.

Julie Hirschhorn, Ph.D., an associate professor in the College of Medicine, directs the Molecular Pathology Lab at MUSC. “BA.4 and BA.5 do seem to have that doubling that we've seen in the past, with certain variants that tend to fight to take over.”

It’s unclear how widespread BA.4 and BA.5 are in South Carolina since the number of people who do home tests instead of going to test sites has gone way up, and there isn’t widespread wastewater surveillance.

The impact of the new Omicron subvariants isn’t clear either. They obviously spread easily, but Hirschhorn said that so far, there’s no evidence that they’re otherwise worse than what was already out there.

“The threat for hospitalization with Omicron appears to be diminished compared to some of the other variants that we have seen. But it's not gone. So people with at-risk conditions could still see hospitalization or death if they were to catch COVID.”

Her lab’s findings come during a COVID wave in the Charleston Tri-county area, one that’s estimated to peak in about a month. “Think about how you need to protect yourself and those around you in any way that you can, whether that be wearing a mask or getting a vaccine or a booster if you're eligible. It might be a good time to consider getting a vaccine or booster if you can,” Hirschhorn said.

“We continue to kind of hold our breath that the variants are going to continue along the same path. Maybe they're a little bit more transmissible, but we're not seeing hospitalizations go up. Variation is not always that predictable, so we’re grateful every time a new variant comes out that doesn’t cause a spike in hospitalizations.”

Glen said they’ll keep sequencing as the coronavirus continues to evolve, to let scientists, health care workers and the public know what they’re dealing with – and maintain their ready stance into the future. “I think it's important that all the infrastructure and tools that have been put in place are maintained in some form or fashion to be able to be spun up again as needed.”