University of South Carolina researchers have developed a model of the coronavirus pandemic showing that masks have stemmed the spread of disease and prevented tens of thousands of infections in places that have adopted them widely.
The team's aim is to put hard numbers on a refrain that public health experts have repeated for months: that masks make a difference and could bring the virus to heel. The lead researcher says he wanted to give decision-makers a clear view of how big that difference is.
That's particularly significant in South Carolina, which doesn't have a statewide mask requirement. Instead, questions about whether to wear a mask are far more localized here. It's up to local governments to decide whether to require them, and for the millions of people here who aren't bound by mandates, wearing a mask is an individual decision.
The USC model, developed by the university's Artificial Intelligence Institute, looks for patterns between the prevalence of COVID-19 in different areas and estimates of how often people wear masks. And it analyzes how broader adoption of masks could shape the course of the pandemic.
In Charleston County, for instance, the model suggests that tens of thousands more people could have been infected with the virus had local governments waited to require masks in public places. Mask ordinances began taking effect here at the beginning of July, when the region was gripped by a spike in cases.
By waiting until the beginning of August, the number of cases of COVID-19 — the disease caused by the coronavirus — could have been more than three times higher in Charleston County, USC’s model says. Likewise, the model suggests that earlier action could have prevented much of the midsummer spike.
Data from the S.C. Department of Health and Environmental Control show that the number of new coronavirus infections peaked in Charleston County shortly after the mask mandates took effect.
The number of new cases per day has fallen by about 90 percent since then. All told, public health officials have confirmed one case of COVID-19 for every 25 residents of the county since the first infection was detected in March.
Biplav Srivastava, the USC professor leading the modeling project, said the tool is meant to highlight the importance of wearing a mask and to give decision makers more information as they consider public health measures.
Dozens of cities and towns in South Carolina require masks, including the state’s largest cities, Charleston, Columbia and Greenville. And 12 of the state’s 46 counties have rules on the books.
DHEC says those areas have fared better as a result. The health department’s analysis in August found that cases fell sharply in areas with mask requirements, while they increased slightly in areas without them. Dr. Linda Bell, the state's top infectious disease official, has said that a statewide mask mandate would improve the situation in South Carolina, The Greenville News reported in July.
“We could get where we needed to be much more quickly, obviously, if we were able to do something statewide all at once," Bell told the newspaper.
In the city of Charleston, which issued one of the state’s first mask mandates, officials have issued 67 citations for mask violations since the mask rules went into effect July 1. The cases, most of which are pending in the city’s municipal court, represent a mix of indoor and outdoor violations, including several tour guides and tourists cited for refusing to wear face coverings, said Dan Riccio, the city’s livability and tourism director.
“I think the enforcement process that is currently ongoing has really contributed to the number of cases declining, especially in Charleston,” he said.
Livability and tourism officers are responding to complaints and looking out for violations on the street, Riccio said. The city is also working closely with the College of Charleston to identify students engaging in large gatherings without masks or social distancing. If officers find violations off-campus, the city notifies the college and passes along the names of those involved for possible disciplinary action, he said.
People overall seem to be complying with the mask ordinance for the most part, Riccio said. He is convinced it has played a role in curbing the spread of the virus in the city.
Glenn Smith contributed to this report.
