Peaking levels of COVID-19 detected in Chapel Hill, Carrboro wastewater

The N.C. Department of Health and Human Services Wastewater Monitoring Dashboard indicated peaking levels of COVID-19 are being detected in wastewater in the Chapel Hill and Carrboro area.

Prior to the current surge, the local record for per-person levels of COVID-19 in wastewater was set at the end of August 2023 and declined soon after. Levels began rising again in November, and the area has one of the highest 15-day rates of wastewater COVID-19 detection increase in the state.

While the recorded samples are not at their highest-ever amounts, the NCDHHS' estimate on the overall levels of COVID-19 in wastewater — accounting for missing data — is at an all-time high.

People with COVID-19 and other viral illnesses shed the virus into their feces after they are infected, often before any symptoms are present. Asymptomatic people can also shed the virus into wastewater, giving medical and public health professionals a potential foreshadowing of virus outbreaks.

Virginia Guidry, the branch head for occupational and environmental epidemiology at the NCDHHS, works closely with the data on the dashboard.

“If you look statewide at the emergency department visits and hospitalizations, and then compare that with the wastewater surveillance numbers, they've all been really high," Guidry said. “The good news is, it looks like they're starting to come down some, but not so much in Chapel Hill and Carrboro. So, at the moment at least our wastewater numbers are still really high.”

Dr. Rachel Laramee, a pediatrician who completed her residency at the UNC Children's Hospital, has seen patients infected with COVID-19 on a daily basis since the start of the global pandemic, but at a reduced rate compared to 2021 and 2022.

“Since we are in the middle of epidemic flu, COVID-19 and RSV season, and people are no longer masking or isolating, COVID-19 can spread more in the population,” Laramee said. “And that's why I think you're seeing greater levels in the wastewater now, compared to the peak of the pandemic.”

Wastewater utilities collect wastewater samples twice a week. Wastewater samples are analyzed in a laboratory to evaluate the accurate levels of the COVID-19 virus, and the amount of the virus is measured by the number of viral gene copies.

“Wastewater surveillance is a new tool, and it really has a lot of potential,” Guidry said. “Keep an eye out on wastewater surveillance because there's a lot of potential for using it for other things as well, like for use on antibiotic resistant organisms, or other infectious diseases like gastrointestinal illness and sexually transmitted infection."

Dr. Brian Bramson, an associate professor of medicine in the UNC Division of Infectious Diseases, works as an infectious disease expert with a clinical interest in COVID-19. He said a rise of COVID-19 infections is likely driven by the newest Omicron variant — which, compared to the other variants, appears more transmissible.

“Wastewater trends can predict increased hospitalizations down the road or prepare hospital systems, public health departments for the need for availability of health care providers to treat people who are sick,” Laramee said. “This variant causes less severe disease, so we might not see an increase in hospitalization. We might just see an increase in the wastewater.”

Hospital admissions for COVID-19 across the state have fallen over the last month, down from more than 900 admissions the week of Dec. 30 to just over 700 the week of Jan. 20.

To combat potential spikes in COVID-19 infections in the future, Bramson emphasized the communal benefit of receiving updated vaccines.

“There are a lot of people who are getting exposed and getting infected,” Bramson said. “Because a lot of people have protection, we're not seeing as many people get sick, but if more people have the updated vaccine, I think we see even fewer people who got sick and probably fewer cases of transmission, as well.”

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