As most people have probably experienced by now, testing for COVID-19 can be uncomfortable, expensive, time-consuming or a combination of all three. The current standard for testing involves a nasal swab to collect a sample from the back of the nose and throat, which is then analyzed for SARS-CoV-2 RNA by a reverse transcriptase polymerase reaction (RT-PCR). This process involves turning RNA into complementary DNA, adding fluorescent dye and then amplifying the DNA. This can indicate whether the virus is present and also how much viral load exists, which correlates to infection severity . In some areas, results can take days, which only exacerbates transmission and mortality rates, while increasing the burden on healthcare systems . Washington University in St. Louis’s saliva test does not require RNA extraction, so results are available in a few hours and can be communicated within a day . However, as the number of cases continues to increase across the country and issues with accessibility advance, testing capacity needs more improvements. This is where the breathalyzer test comes in.
Multiple research groups have developed a nanomaterial-based sensor that detects COVID-19 through disease-specific biomarkers . Specifically, viruses and the cells they infect release volatile organic compounds (VOCs) that can be detected in an exhaled breath. Researchers linked an array of gold nanoparticles to molecules that are sensitive to various VOCs. Molecular interactions with the VOCS lead to changes in electrical resistance, which can then be detected by a sensor. In Wuhan, China, the machine was trained with 49 confirmed COVID-19 patients and 58 positive controls, along with 33 patients with lung infections but not COVID. In testing, the device has 76% accuracy in distinguishing positive cases from the control and 95% accuracy in distinguishing positive cases from lung infections. There was also 88% accuracy for discriminating between sick and recovered COVID-19 patients. The promise in this technology lies in its affordability, its potential for widespread distribution and increasing accuracy rates.
A company in Singapore has been developing a breathalyzer test that will employ this technology. A clinical trial of their Breathonix device has shown an overall sensitivity of 93% and a specificity of 95% . They liken the technology to creating a bio-fingerprint of COVID-19 through machine learning and see promise in high-traffic areas like airports and hotels, where they hope to incorporate disposable mouthpieces and one-way valves along with the breathalyzer. Even if the accuracy does not improve, it can be useful to screen large populations to decide who needs to undergo further testing .
Texas A&M is one of the colleges pioneering this effort, although the technology is still in the process of FDA approval for widespread use. The testing device the researchers developed looks like a kiosk where individuals use a disposable straw to blow into a copper tube. Results can be sent to one’s personal cell phone in less than a minute and the copper tube is superheated between tests so future results are not contaminated. Currently, there are five kiosks on Texas A&M’s campus, and the mobility of the kiosk holds promise for bringing the device to large group settings such as concerts, sporting events and religious services . Preliminary results show the accuracy is comparable to PCR tests, the current standard for diagnosis .
The University of Miami has a similar setup, where participants breathe a few puffs into a disposable, sterile TeraTube. The sample is sealed and fed into a BioSafety station to analyze the test in less than one minute and at the same cost as a cup of coffee. When students participate in their routine nasal swab test, they are also asked to use the breathalyzer for comparison of accuracy to the RT-PCR .
The chair of the Miller School of Medicine at the University of Miami, Roy E. Weiss, highlights the benefits: “It’s as simple as a kazoo—you just blow into it… It would allow us to test at a fraction of the cost and time of our current nasal swab test and as frequently and wherever necessary. There could even be stations before a football game. People would blow into the tube, get their results in a minute, and then if they’re negative, go in and enjoy the game” .
There are a variety of benefits beyond social interactions. Often more sophisticated and advanced tests are used to verify results from these more basic preliminary tests, but increased accuracy in breathalyzers could reduce the number of unnecessary confirmatory tests. There would also be decreased burden and exposure risk for hospitals, as symptomatic and anxious asymptomatic patients that enter the emergency room could be quickly tested or even sent back home if they were not in distress. There would be an improvement in the efficacy of point of care facilities, where testing and patient care are provided on site in the same visit. Thinking ahead, this could be applied to other disease infection models as a diagnostic tool in the case of a new outbreak .
Erin Kobetz, the vice provost for research and scholarship at the University of Miami, expands on this by saying, “if approved, this test could provide the opportunity to assess risk in real time, which may help us more effectively curb transmission” . Individuals are constantly being forced to make risk assessments. Is it okay to take public transportation just a couple of stops? If I take a sip of my coffee inside, what are the odds the stranger next to me is infected? The breathalyzer test would help to curb this constant worry with the knowledge that people are only let into areas after they have received negative results. Of course, there still must be caution, but breathalyzer tests compounded with social distancing efforts could decrease virus spread.
Although more testing is needed to determine the efficacy of these devices, it acts as a small step towards the normalcy we yearn to return to and serves as a reminder of the unrelenting efforts of the scientific community during this pandemic. The breathalyzer’s appeal comes from its ease of use, accessibility and distribution. As we begin to immunize the population, we must simultaneously focus on mitigating transmission among those still vulnerable and looking towards future public health crises in the context of emerging technology.
Edited by: Rehan Mehta
Illustrated by: Alexandra Laufer