Estimated number of active COVID infections in Tri-county area tops April peak

June 10, 2020
Graph shows rising growth rate of COVID-19 in the Tri-county area.
This graph from the MUSC COVID-19 Epidemiology Intelligence Project shows a steep increase in the estimated number of active cases in the Tri-county area over the past week.

New data out of the Medical University of South Carolina shows the estimated number of active COVID-19 infections in the Tri-county area has recently topped the April peak. It is estimated that more than 416  people in Berkeley, Charleston and Dorchester counties may currently be infected.

Meanwhile, the seven-day average growth rate of confirmed infections from day to day has risen to about 3.6% in the Tri-county area. That may sound low but it’s actually up substantially from the .6% growth rate of just a few weeks ago. Growth rate refers to how quickly the number of COVID-19 infections is increasing.

Michael Sweat, Ph.D., directs the Center for Global Health at the Medical University of South Carolina. He’s worried the growth rate will keep climbing. “If you get growth rates up above 5%, you start having an explosive epidemic happening very rapidly.”

But Sweat said that is not a foregone conclusion. He also pointed out the Charleston area has a relatively low number of people with the illness caused by the new coronavirus, about 416 active infections compared to the 775,831 people who live in the area. “It’s important to note that it’s currently manageable even as it’s going up, in terms of the impact on the health system. But it’s always a worry when these numbers are going up.”

Dr. Michael Sweat 
Dr. Michael Sweat

Sweat leads the MUSC COVID-19 Epidemiology Intelligence Project team, which was formed to analyze trends, give information to help government and business leaders make decisions and help hospitals and clinics prepare for COVID-19 patients. It puts out a situation assessment each Wednesday, available to the public online.

The number of active cases in the Tri-county area first peaked about two months ago at 368, Sweat said. “Then it just dropped. That’s because a few weeks before, the lockdown happened. It usually takes three to seven days before people become symptomatic. So these numbers are often reflecting what’s happening several weeks before.”

Now that more people are out and around again during a period that included the Memorial Day holiday weekend, the Tri-county area has hit a new peak. “We’re at an important juncture. That could just keep going up and up. We don’t know. It could flatten out.”

Sweat said the increase is not surprising. “With more opening up, more people getting out, going back to work, restaurants opening with limitations, we were likely to see an increase.”

Sweat said recent protests about the deaths of George Floyd and other African Americans have also brought people together in large numbers, and that could add to the positive cases in the next few weeks. 

Protesters seem to be aware of the risk. This past Monday, after a weekend of protests in the Charleston area, the number of people seeking COVID-19 testing through MUSC Health Virtual Urgent Care was up 200%.

Sweat said the fact that the protests were outside could help. “You’re at much greater risk inside. Bars and churches have been the scene of big super-spreader events. A super-spreader is typically somebody who’s newly infected, infectious and doesn’t have any symptoms. They often lead to massive outbreaks. Mardi Gras was an example of that.”

While Sweat and his team keep a close eye on the coronavirus growth rate in Charleston, they’re also watching what’s happening statewide. MUSC Health has clinics and hospitals across South Carolina. And what Sweat is seeing, in some cases, concerns him.

“Florence had a big problem for some time that only recently stabilized. Lancaster has been the sleeper. It was always a low-grade epidemic. They just had an explosion of growth recently. We’re about to intervene — to sound the alarm,” he said, referring to MUSC Health leaders who are in close communication with their counterparts in Florence and Lancaster. “We’re trying to understand what’s coming next.”

Sweat said if the numbers keep going up in South Carolina, more tough choices will come into play. “What do the politicians do? What do the businesses do? How do you put the brakes on? How do you slow things down?” 

His advice for everyone right now: be careful. “We’re seeing these increases. They’re moving very quickly. The problem is, it takes several weeks to detect. If it blows up, you really won’t know it for a week or two. So I think it’s smart to be a little cautious. I don’t think you can shut your life down completely. Trying to figure out how to go forward is important."

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