Masks, physical distancing, good hygiene, and ventilation can help reduce the transmission of COVID-19 in public places. But even when these measures are taken, scientists have sometimes detected SARS-CoV-2, the virus that causes COVID-19, in indoor settings.
Now, Yale School of Public Health (YSPH) researchers have developed a passive air sampler clip that can help assess whether a person has been exposed to SARS-CoV-2, which could be especially helpful for workers in high-risk settings, such as health care facilities and restaurants. The device is described in the American Chemical Society journal Environmental Science & Technology Letters.
“The Fresh Air Clip is a wearable device that can be used to assess exposure to SARS-CoV-2 in the air,” said the clip’s creator Krystal Godri Pollitt, an assistant professor of epidemiology (Environmental Health Sciences) at YSPH and an assistant professor of chemical and environmental engineering at Yale.
“With this clip we can detect low levels of virus that are well below the estimated SARS-CoV-2 infectious dose,” Godri Pollitt said. “The Fresh Air clip serves to identify exposure events early, alerting people to get tested or quarantine. The clip is intended to help prevent viral spread, which can occur when people do not have this kind of early detection of exposure.”
COVID-19 is primarily transmitted through the inhalation of virus-laden aerosols and respiratory droplets that infected individuals expel by coughing, sneezing, speaking or breathing. Researchers have used active air sampling devices to detect airborne SARS-CoV-2 in indoor settings; however, these monitors are typically large, expensive, non-portable, and require electricity. To better understand personal exposures to the virus, Godri Pollitt and her colleagues sought to develop a small, lightweight, inexpensive, and wearable device that doesn’t require a power source. The Fresh Air Clip was the result.
The device captures virus-laden aerosols that deposit on a polydimethylsiloxane (PDMS) surface. The team tested the air sampler in a rotating drum in which they generated aerosols containing a surrogate virus, a bacteriophage with similar properties to SARS-CoV-2. They detected virus on the PDMS sampler using the polymerase chain reaction (PCR) protocol, showing that the device could be used to reliably estimate airborne virus concentrations.
In further testing, the researchers distributed Fresh Air Clips to 62 volunteers, who wore the monitors for five days. PCR analysis of the clips detected SARS-CoV-2 RNA in five of the clips: Four were worn by restaurant servers and one by a homeless shelter staff person. The highest viral loads (more than 100 RNA copies per clip) were detected in two badges from restaurant servers. These results indicate that the Fresh Air Clip could serve as a semiquantitative screening tool for assessing personal exposure to SARS-CoV-2, and also help identify high-risk areas for indoor exposure, the researchers report in their study.
“The Fresh Air Clips are easy-to-use, non-invasive, and low-cost,” Godri Pollitt said. “These features make it easier to scale-up this kind of exposure monitoring for COVID-19 and other respiratory viruses so that the clips can be made available across larger groups of workers in high-risk jobs, such as restaurant servers, health care workers, and teachers.”
The Fresh Air Clip is currently being used in other research projects. Godri Pollitt said she hopes to make the clips available to the public in the future.
This research was supported by the National Science Foundation (NSF) and the Rothberg Fund. Dr. Jodi Sherman, associate professor of anesthesiology and of epidemiology (Environmental Health Sciences) at Yale and Jordan Peccia, Yale’s Thomas E. Golden Jr. Professor of Chemical & Environmental Engineering, were co-investigators on the NSF grant supporting this research. Yale doctoral student Darryl Angel and postdoctoral associate Dong Gao were co-first authors on the paper.