No summer slump: Explosive growth, new age group affected in latest Tri-county COVID assessment

July 02, 2020
Graph showing increase in COVID infections
Public health expert Dr. Michael Sweat hopes greater public awareness will convince more people to take the rising coronavirus rate seriously.

The trajectory of the coronavirus in the July 2 update from the Medical University of South Carolina’s COVID-19 Epidemiology Intelligence Project makes April’s “wave” of cases in the Tri-county area look more like a ripple. 

There’s also been a dramatic shift in the age range of many of the people who are testing positive.

Michael Sweat, Ph.D., directs the public health project at MUSC. It analyzes COVID-19 data and trends in the Charleston Tri-county area, provides perspective and offers predictions to help guide health care and policy decisions.

Dr. Michael Sweat 
Dr. Michael Sweat

“About 74% of all infections in the Charleston area since the pandemic started have been diagnosed since mid-June,” Sweat said. “It’s rapid, explosive growth. Of the 6,171 total cases in the Tri-county area as of July 1, 4,547 have been since mid-June.”

Sweat pegs the growth rate at about 8%. “That’s a really big number. If you keep it at that number, it just keeps growing. We end up with large numbers of cases.”

A key factor in that growth is the coronavirus’ spread among young adults. “There’s definitely this marked change in the demographics of who is showing up infected right now,” Sweat said. “Older people are not showing up as new infections nearly as much as younger people. About 47% of infections being diagnosed right now in Charleston County are among people 30 and below. Berkeley and Dorchester counties are about the same.”

He has a theory about that. “I think older people are being more cautious because they’re more concerned about the impact of the coronavirus. Young people like to get out and interact with people. They’ve been pent-up for a long time. I think when the state reopening was approved, people just got out. And I believe a lot of younger people got infected. Now we’re seeing this wave of them coming in to be tested.”

Sweat said young people are less likely than older people to have severe symptoms. That’s good news for them. But it also means there may be even more of them in the Lowcountry who aren’t getting tested because they don’t realize they have the virus. 

“The frequent lack of recognition of mild symptoms as COVID could be leading to even further spread. We know that people who are mildly symptomatic, maybe they think they just have allergies or aren’t feeling great for a day or two, may be accounting for a lot of transmission. That’s something we really need to watch,” Sweat said.

“I anticipate we’re going to start seeing older people catching it from younger people. That’s what’s likely to happen, particularly within households. About 60% of cases diagnosed are from interhouse transmission.”

Sweat said the idea floated early in the pandemic that the virus might ebb during the summer is not panning out, at least not in the Lowcountry. And its rapid spread makes what he calls tools for fighting the virus harder to use. That could affect everybody, not just people who come down with the virus.

“As these numbers get bigger, it becomes less feasible to contact trace and test rapidly. Then, the only tool you have is lockdown. I know there’s zero political will for it, but that may change. You’re seeing Texas and other states back off opening up. If it gets bad enough, there’s nothing you can do but institute a strict lockdown. I hope we don’t have that, but once those numbers start getting large, you just lose our tools to roll them back. I’m afraid we’re on that path.”

But Sweat said that’s not inevitable. “I have faith in people that they’re going to change their behavior. They’ll learn the seriousness from this outbreak. The main thing that historically gets people to change behavior is personal knowledge of people affected. That’s going to happen more and more as we see larger numbers.”

About the Author

Helen Adams

Keywords: COVID-19