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A decade ago, when firefighter John Burke earned his master’s degree in health care emergency management, he wrote his thesis on pandemic planning. So when the coronavirus hit last spring, Burke, now the fire chief in Sandwich, Massachusetts, was ready.
“I had my playbook ready,” Burke said.
Testing for the virus was a top priority, so it connected with a private lab to make sure its firefighters, who were transporting coronavirus patients to hospitals, could be tested regularly.
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And then you heard that Thermo Fisher Scientific, a Massachusetts company that makes laboratory equipment and supplies, was testing an air sample that could help you detect airborne coronavirus particles.
By December, he had installed one in the hallway of a fire station. The device, the size of a toaster oven, sucked in ambient air and trapped airborne virus particles, if any, in a specialized cartridge. Every afternoon, an employee would pick up the cartridge and escort it to the UPS mailbox across the street, and send it off for lab analysis.
Before the month was out, the air sampler had detected traces of the virus. Officials eventually traced him to a city employee who had been working at the station, without a mask, during a quiet vacation period.
It was a proof of concept for Thermo Fisher Scientific’s AerosolSense Sampler, which the company made available to the public on Wednesday. The device, the company says, can be used to detect a variety of airborne pathogens, including coronavirus. It could be deployed in hospitals, offices, schools, and other buildings to monitor for signs of the virus as society begins to reopen.
The AerosolSense, which will sell for $ 4,995, is not the first air sampler capable of capturing the coronavirus; Scientists have used several other models to study the pathogen over the past year. But the new device appears to be simpler and more accessible, experts said.
“I’m not sure there is anything else on the market that is that easy to use,” said Linsey Marr, an airborne virus expert at Virginia Tech. “This will allow for the collection of air samples by almost anyone.”
Thermo Fisher Scientific is likely to face the competition. The pandemic has sparked interest in a once-niche area of disease surveillance: pulling pathogens out of nowhere. Experts in the field say they have been inundated with calls and emails from companies, organizations and other labs interested in developing or using air samplers for coronavirus collection. (Marr is consulting with a company, whose name he could not reveal, to develop an air sampler that would monitor the virus in public places.)
And in November, the Defense Advanced Research Projects Agency began soliciting research proposals to develop an air sensor that detects the coronavirus.
“There is great interest,” said John Lednicky, a virologist at the University of Florida.
The approach has real potential, experts say. But it also raises a tangle of logistical issues, they add, and it must be implemented with care, with a clear understanding of what technology can and cannot do.
Air samplers are already widely used to detect a variety of contaminants. But catching viruses in the air is considerably more difficult. Viral aerosols are tiny and make up only a small fraction of the debris that floats in the air.
“You’re looking for a needle in a haystack in a haystack field,” Marr said.
That means that most air samplers need to inhale a lot of air to capture virus fragments, and even then they may not capture viruses present at low levels.
The technology is improving, experts said, but it remains complicated and labor-intensive.
“There are very few places that have the virology knowledge, equipment and capacity to do this correctly,” Lednicky said.
The AerosolSense sampler was designed to be easy to use. The device draws air into a collection tube and directs it into a replaceable cylindrical cartridge. The cartridge, which is about the size of a 10 milliliter syringe, contains a proprietary foam-like substance that traps viral particles.
After a few hours or more, the cartridge can be removed from the machine and sent to a laboratory for analysis. Technicians can use PCR, the polymerase chain reaction technique that underlies the gold standard test for COVID-19, to determine if genetic material from the coronavirus is present.
It can take a day or two to receive results if the cartridge has to be shipped to a third-party lab, but hospitals, universities, and nursing homes that have on-site labs can process cartridges in a few hours, Thermo Fisher Scientific says.
The company has also performed “initial feasibility tests” with a rapid PCR test that gives results in 30 minutes. (The test is performed by Mesa Biotech, recently acquired by Thermo Fisher Scientific.)
A series of studies, conducted in a closed box, a 9-by-14-foot room and hospital rooms of COVID-19 patients, suggested that the AerosolSense sampler could capture the coronavirus even when it is present at low levels, Kevin Van said. Den. Wymelenberg, who conducted the research and directs the Center for Biology and Built Environment at the University of Oregon.
“We are confident this is sensitive enough to be used in real world settings with COVID positive people,” he said.
Thermo Fisher Scientific also tested the samplers at a COVID-19 field hospital in Worcester, Massachusetts. The hospital installed the devices in patient care areas, where the virus was expected to be found, and in staff break rooms, where it was not.
“Our cold zones were really cold,” said Dr. John Broach, an emergency physician at UMass Memorial Medical Center and medical director of the field hospital. “And our hot zone had heavy contamination, which was to be expected.”
Thermo Fisher Scientific, which will focus on hospitals in the first phase of its deployment, says that other healthcare facilities could use the samplers to make sure their COVID protocols are working and that the virus is not leaving hospital rooms. patients.
“We see facilities wondering, are their scheduling and screening activities effective?” said Mark Stevenson, executive vice president and chief operating officer of Thermo Fisher Scientific. “Are your cleaning and ventilation procedures adequate? And consequently, can I give my patients confidence in their visit to the facility? “
Of course, detecting the virus in the hospital room of a COVID-19 patient is one thing, said Alex Huffman, an aerosol scientist at the University of Denver: lower, keep an eye on a classroom or a medical clinic where you have no idea if there will be someone positive or not. “
And an air sampler isn’t a silver bullet, said Burke, who made sure his firefighters continued to wear masks, socially distance themselves and get regular COVID tests even after he installed the air sampler.
“It can’t be like a smoke detector in your house where you say, ‘I’m just going to have the machine, I’m not going to do anything else, it will alert me when there is a problem,'” he said.
There are no truly autonomous viral samplers yet, which still require humans to extract and analyze the samples. That takes time and means that the results provided by these samplers are not real-time snapshots, but composite portraits of a building during the previous two, 12, or 24 hours.
And while PCR analysis can reveal whether coronavirus genetic material is present, it cannot distinguish between intact and infectious viruses and viral fragments that pose no risk.
Neither of these inconveniences is a deal breaker, said Marr, who noted that it was still useful to know whether airborne coronavirus particles were in a space recently.
“If they have detected it in the air, then it has probably been aired quite recently,” he said. “And I would be willing to bet that there is some infectious virus there.”
Results must be interpreted with care. A negative result does not mean that there is no virus present, it simply means that the air sampler did not collect any.
“There is a high probability of false negatives, because the viruses are in remarkably low concentrations in the air,” said Kristen Coleman, a bioaerosol expert at the Duke-NUS School of Medicine in Singapore.
Figuring out how to respond to a positive sample could be even more difficult.
“I don’t think the answer is simply to evacuate the building,” Van Den Wymelenberg said.
Instead, he envisioned a more measured set of responses, from increasing ventilation rates to strategic testing and tracing, that organizations could adopt when they found signs of the virus.
But convincing office workers that a temporary increase in ventilation makes it safe to enter an office where the virus has been found could be hard to sell. And even these modest measures could raise concerns about privacy and legal liability.
“I have been talking to several large building owners about indoor environmental monitoring during this pandemic, and the question always arises as to how this information will be used and who is responsible for any misapplication of the information,” said Van Den Wymelenberg.
(Burke made sure to authorize the use of the air sampler with local unions, which were, he said, “100% supportive.”)
Another approach could be to use air sampling for larger-scale surveillance. If public health authorities see an increase in viral levels in a certain region or neighborhood, this could be an early warning sign that an increase in new COVID-19 cases is coming, and that officials should intensify their testing. and contact tracing.
Easy-to-obtain and easy-to-use air samplers could also enable more scientists to conduct research on viral aerosols, Huffman said.
“In the medium and long term, I think technology like this has a tremendous role to play in continuing to drive the state of knowledge about these things, so that we can make better decisions that help with other viral aerosols, like influenza and the following. . coming pandemic, ”he said. “That is not to say that he cannot help now, but I think his real influence may be even greater as we go further and further into the future.”
This article originally appeared in The New York Times.
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