'I'm concerned we could be in a silent epidemic'

May 12, 2022
COVID particle under what looks like blue liquid. iStock
What lies beneath the surface of reported COVID cases in the Charleston Tri-county area? A lot more cases, an MUSC scientist fears. iStock

After holding steady in last week’s update, COVID cases jumped 121% in the Charleston Tri-county area in this week’s report from the Medical University of South Carolina’s COVID-19 Epidemiology Intelligence Project.

“I'm concerned we could be in a silent epidemic,” said team leader Michael Sweat, Ph.D. “We're seeing 16 cases per day per 100,000 people, which is a modest number of cases, but it could be five times that number.”

His team makes its calculations based on a weekly release of data from the South Carolina Department of Health and Environmental Control. It usually comes out on Tuesday but was delayed by a day this week because of a state holiday.

Sweat said there’s no question the number of cases is higher than the reported number. How much higher remains unclear. Self-test results don’t go to DHEC, so their total remains a mystery.

He said the percentage increase, 121%, may be the best metric to monitor. “When you start to see big percentage increases, it’s worrying.”

Another indicator he’s tracking: the number of people in the hospital with COVID. Infectious disease specialists at MUSC Health recently said an uptick started after local schools’ spring breaks and Easter weekend. Sweat said it hasn’t stopped.

Dr. Michael Sweat 
Dr. Michael Sweat

“I think we're seeing a true increase in hospitalizations. Numbers are still pretty small, but the growth rate's pretty big — and that's a lagging indicator. So it's probably been brewing out there in the community for a while. And then our case count, which is clearly undercounting is also getting up there and growing fast. So it's all adding up to say that the trends are not good. They're going up.”

He said a key question is how high hospitalizations will go. Vaccinations, boosters and recent COVID infections will all play a part. “There's a lot of immunity. We might see fewer hospitalizations than last time.”

We also have antiviral drugs, which can lessen the severity of symptoms and reduce your odds of ending up in the hospital.

But Sweat said this is a good time for people concerned about COVID to take precautions. “If you're vulnerable — you have comorbidities, you're on immunosuppressants or you’re immunocompromised — now is the moment to be a little careful.”

He said it’s all about your level of risk tolerance, whether you have a vulnerability or not. “Where the real risk is, from most of the studies, is crowded rooms, particularly where people are talking loudly. So bars and restaurants that don't have very good ventilation. Meetings, like the Gridiron Club dinner, where you get a lot of people in a room — you're amplifying the probability of picking it up.”

At least 30 people tested positive for COVID after the Gridiron Club dinner, including the U.S. attorney general, the U.S. commerce secretary and members of Congress, according to a report in the Washington Post.

Sweat is also keeping an eye on a pair of Omicron subvariants that are driving up cases in South Africa: BA.4 and BA.5. “With BA.2 and BA 2.12.1, you were pretty protected if you had had the Omicron variant from before. But BA.4 and 5 seem to be evading immunity. They will get around the world. We just know that happens relatively quickly.”

BA.2 and BA.2.12.1 are Omicron subvariants that have shown up in testing at MUSC. BA.4 and BA.5 have not been detected here.

Sweat, a professor in the College of Medicine at MUSC, an adjunct professor at the Johns Hopkins Bloomberg School of Public Health and a former research scientist with the Centers for Disease Control and Prevention, said COVID has been coming in waves about every six months. Our last wave peaked in mid-January.

“I think we're likely to see this one continue to go up — but probably not anywhere near as high as it went during our last wave, I think, in terms of infections.”

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