HVAC-Based Air Sampling Proves its Potential for Warning of SARS-CoV-2 Exposure in Buildings

A minimum 75 percent success rate at detecting exposure to individuals later testing positive for COVID-19 proves its worth.

A team of scientists from East Carolina University and the North Carolina Agromedicine Institute have discovered a new way to detect the SARS-CoV-2 virus responsible for COVID-19 — by sampling the air passing through building ventilation systems.

"I think it’s important," Rachel Roper, PhD and professor in the university's Department of Microbiology and Immunology, explains of the work, which can provide early warning of potential exposure, "because you want to know if someone in the building is infected, potentially contagious and infecting other people, so it’s a really important public health measure."

Sampling the air from HVAC systems could provide early warning of SARS-CoV-2 exposure. (📹: ECU)

"Detection in air provides advance notice of potential exposures in specific locations within a building," adds Mike Van Scott, interim vice chancellor for ECU’s Division of Research, Economic Development and Engagement. "It was fortuitous that SARS-CoV-2 could be detected in wastewater, but the next respiratory virus that we encounter may not be as stable, and detection in air would allow us to respond quickly."

To prove the concept of detection in ventilation systems, the team collected air samples from two student dorms and an isolation suite which had been home to students known to have tested positive. The 248 samples, across four collection methods, tested positive 100 percent of the time for samples taken from the isolation suite and 75 percent of the time for samples taken from the dorm when a student on the same floor later tested positive for COVID-19 via nasal swab.

"HVAC air sampling can be an important surveillance technique for the control of viral spread in large buildings, especially congregant living settings," the team explains in the paper's conclusion. "Such monitoring of air may allow early intervention to stop the spread of SARS-CoV-2 inside buildings. Future building designs should include HVAC access for such sampling, and public health policies should consider implementation of HVAC surveillance testing either routinely or during times of contagion."

The full paper is available to read on the website of the American Journal of Infection Control under open-access terms.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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