Whether it is a PCR test or the at-home variety, sending a swab up the nose to swirl around and test for COVID-19 has become a familiar but uncomfortable part of living through the pandemic.
However, what if there was an alternative?
For the first time, health authorities in the United States have given the green light to a COVID-19 breathalyser, a device promised to deliver results in less than three minutes.
As new sub-variants once again push up case numbers, some experts hope it will be the first of many new tools to diagnose and, therefore, improve the way we live with the virus.
There is even hope breath testing could eventually be used to detect and monitor other conditions, such as cancer.
So just how advanced is the technology? And could it actually replace the nasal swabs we have come to know and loathe?
Breath test with a catch
The US Food and Drug Administration (FDA) has granted emergency use authorisation for a breathalyser produced by small Texas-based company, InspectIR.
The test involves exhaling through a disposable straw into a device the size of a carry-on suitcase which then analyses so-called “volatile organic compounds” associated with the SARS-COV-2 infection.
“Essentially, when your body is fighting the illness, at a cellular level it creates off gas,” co-founder and president John Redmond told the ABC.
“That gas is carried through your bloodstream to your lungs, and then is exhaled as waste. And, based on the sensitivity of our instrument, we can actually see that chemistry.
“And, based on analysis, we can determine if a person is sick or not.”
The test has limitations. The FDA requires that it is conducted by a trained operator under the supervision of a healthcare provider and positive results are supposed to be confirmed by a PCR test.
The cost of leasing the machines has not yet been made public, although the company insists it will be comparable to rapid antigen tests.
Either way, it is a major step forward according to Cristina Davis, a professor of mechanical and aerospace engineering at University of California Davis who is developing her own COVID-19 breath test.
“The way that there are dozens of at-home, over-the-counter COVID rapid antigen tests, I believe that there will be many [breath] devices that will come onto the scene at some point in the next year or year and a half,” she says.
Professor Davis wants to see them used as screening tools at crowded venues such as stadiums or airports, with guests asked to wait several minutes for their result before entering.
It is hoped they could also help to prevent so-called “superspreader” events, such as the exclusive dinner in Washington DC earlier this month where more than 70 people — including members of Joe Biden’s cabinet — are thought to have been infected.
Breath testing could be used for the flu, cancer as well as COVID-19
As it has done for other innovations — such as mRNA vaccines and telehealth — the pandemic has helped to focus attention and funding on breath research.
Perena Gouma, a professor of materials science and engineering, was working on a breath test to detect the flu when COVID-19 began.
“I received a phone call from the White House. They had read my flu breathalyser paper and they said, ‘Can you make a test for COVID-19?'” Professor Gouma says.
She and her team at Ohio State University have since developed a test that, she says, can be self-administered and return a result in less than 30 seconds.
Her test measures the make-up of various compounds in a person’s breath to determine whether or not they have COVID-19 and how severe it is.
Professor Gouma argues the test has a high accuracy rate and could “revolutionise” COVID-19 screening if it was rolled out widely.
However, her efforts to obtain emergency use authorisation from the FDA have so far been unsuccessful.
“I’m a little bit furious because — after having spent two years really working on this technology day and night, and making everything so available to everybody, so transparent — then we got this result,” she says.
The FDA says it does not discuss the status of pending applications.
Professor Davis says the scientific community is only just scratching the surface of the field’s potential.
Eventually, she hopes breath testing could be used to diagnose or monitor conditions such as cancer.
“Breath research doesn’t have to just be about the lung, interestingly, because what we’re measuring from the exhaled breath is really representative of the entire body,” Professor Davis says.
“It’s not just about diagnostics, I think going forward we’re going to see monitoring as a key thing.
“If you’re taking a treatment for something, you could be monitoring, ‘OK, how’s that working?’
“It just gives more information to doctors so that they can help patients individually manage their own health conditions.”
At-home testing leads to COVID-19 blind spots
COVID-19 testing has come a long way since the start of the pandemic, with RATs now relatively widely available alongside the “gold standard” PCRs.
However, while access has improved, some experts fear an increasing reliance on at-home testing has also made it more difficult for authorities to track case numbers.
And that could mean they are less prepared for further waves.
“We are vastly under-counting what is going on in this country,” says Maureen Miller, an epidemiologist at Columbia University’s Mailman school of public health.
“I mean, it is great to have the technology so you can test at home, so you can protect yourself and those around you.
“But several recent studies have shown that people who test at home, [only] between 7 and 10 per cent report their results. Perversely, positive people tend not to report their results.”
Case numbers are not the only measure used to track COVID-19, with hospital admission rates and wastewater surveillance also used to monitor its spread.
More than two years into the pandemic, the Centers for Disease Control and Prevention have set up a new forecasting headquarters, aimed at becoming “the equivalent of the National Weather Service for infectious diseases”.
However, as new Omicron sub-variants drive another increase in cases, Dr Miller is concerned that the US is not as prepared as it could be.
“Will it be this enormous bump? No,” she says, comparing it to Omicron’s peak at the beginning of this year.
“But will it prolong the pandemic longer than it has to? Yeah, it’s definitely going to do that.”
ABC News, 26 April 2022