RALEIGH, N.C. (WNCN) — Getting a group of people together in the tiny town of Grassy Creek or in Mount Tabor comes with a substantial risk of catching COVID-19.
According to a pair of statewide risk maps assembled by the team of researchers at NC-COVID.org, the chance someone is infectious in a group of 25 people is greatest in those two places.
With the holidays approaching, state leaders are urging North Carolinians to be cautious with travel and family gatherings because those small groups are, at least in part, driving the current surge of COVID-19 infections.
The state on Wednesday reported some grim COVID-related numbers, among them a record number of hospitalizations, the second-highest number of new cases and the highest statewide percent positive rate since mid-July.
Paul Delamater — a professor at the University of North Carolina who studies population health issues and infectious diseases, and one of the leaders of the project — said the map was developed to give people another tool as they make holiday plans.
“What I’ve been trying to make here are things that are usable information, taking some of the data that’s publicly available from the dashboard that the Department of Health and Human Services has and maybe doing some translation,” Delamater told CBS 17 News.
This map attaches a number to the percent chance that someone in a group of either 10 or 25 people has COVID-19 and is infectious.
“I saw an opportunity to create something that maybe people could use when they’re making decisions about what they want to do about Thanksgiving this year,” Delamater said.
The color-coded map takes into account the case counts for each of the state’s nearly 800 ZIP codes during the previous 10 days, factors in the team’s estimate of how many people are infectious but are not showing up in the total of lab-confirmed cases and calculates the probability that one person in groups of those sizes is infectious with the coronavirus.
It was inspired by a similar national map produced by researchers at Georgia Tech that calculates risk at the county level, but goes into even more granular detail.
“I was just clicking through and saw that they had been calculating risk, what would be the risk that you came into contact with someone who was currently infectious with COVID based on various event sizes,” Delamater said.
The map resembles the County Alert System Report released earlier this week by the Department of Health and Human Services, which uses a color-coded scale to display the level of risk of infection in each county.
On that map, 10 of the state’s 100 counties are in the red tier, meaning they have at least 200 new cases per 100,000 people over the previous two weeks with a hard number of at least 42 cases during that span, and a percent positivity rate of at least 10 percent or a high impact on county hospitals.
On the NC-COVID.org map, two ZIP codes are colored in the darkest shade of red, meaning the risk is highest: In a 25-person group, the chance of having at least one infectious person in Grassy Creek in Ashe County is nearly 70 percent. In Tabor City, it’s 67 percent.
Some of the higher percentages can be found in the mountains and in the southern Sandhills. But across most of the state, the chances of an infectious person in a group of 25 people is higher than 10 percent.
Transmission has been happening “at smaller gatherings and (in) rural regions, so I am concerned about people thinking, ‘Oh, Thanksgiving is safe, I live out and away from the city and we don’t have a lot of people here,’” Delamater said. “So I am a little concerned about Thanksgiving this year.”