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The New York Times
The next tip: get the coronavirus out of thin air
Ten years ago, when firefighter John Burke received 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 Sandwich, Massachusetts fire chief, was ready. “I had my playbook ready to use,” Burke said. Testing for the virus was a top priority, so he logged into a private lab to make sure his firefighters, who were transporting coronavirus patients to hospitals, could be tested on a regular basis. Sign up for the New York Times The Morning newsletter And then he heard that Thermo Fisher Scientific, a Massachusetts company that makes laboratory hardware and equipment, was beta testing an air sampler that could help it. to detect coronavirus particles suspended in the air. In December, he had installed one in the hallway of a fire station. The device, about the size of a toaster oven, sucked in ambient air and trapped airborne virus particles – if any – in a specialized cartridge. Each afternoon, an employee would remove the cartridge and drive it to the UPS drop box across the street, sending it for lab analysis. By the end of the month, the air sampler had detected traces of the virus. Authorities eventually traced her to a city employee who worked at the train 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 was making available to the public on Wednesday. The device, according to the company, can be used to detect a variety of airborne pathogens, including the coronavirus. It could be deployed in hospitals, offices, schools and other buildings to monitor for signs of the virus as the company 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’s anything else on the market that’s this easy to use,” said Linsey Marr, an airborne virus expert at Virginia Tech. “This will allow almost anyone to collect air samples.” Thermo Fisher Scientific is likely to face competition. The pandemic has galvanized interest in a once niche area of disease surveillance – extracting pathogens out of nowhere. Experts in the field say they have been inundated with calls and emails from businesses, organizations and other labs interested in the development or use of coronavirus collection air samplers. (Marr is consulting with a company, the name of which she could not disclose, to develop an air sampler that would monitor the virus in public places.) And in November, the Defense Advanced Research Projects Agency began soliciting proposals research to develop coronavirus. -detection of the air sensor. “There is tremendous interest,” said John Lednicky, virologist at the University of Florida. The approach has real potential, experts say. But it also raises a thicket of logistical questions, they add, and needs to be deployed with care, with a clear understanding of what technology can and cannot do. Air samplers are already widely used to detect a variety of pollutants. But capturing airborne viruses is much more difficult. Viral aerosols are tiny and make up only a small fraction of the detritus that floats in the air. “Looking for a needle in a haystack in a field of haystacks,” Marr said. This means that most air samplers have 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 is still complicated and labor intensive. “There are very few places that have the virology knowledge, equipment and capacity to do this properly,” Lednicky said. The AerosolSense sampler was designed to be easy to use. The device draws air through a collection pipe and directs it to a replaceable cylindrical cartridge. The cartridge, which is roughly the size of a 10 milliliter syringe, contains a proprietary foamy substance that traps virus particles. After a few hours or more, the cartridge can be removed from the machine and sent to a lab for analysis. Technicians can use PCR, the polymerase chain reaction technique that underpins the gold standard test for COVID-19, to determine if genetic material for the coronavirus is present. It may take a day or two to receive the results if the cartridge needs to be shipped to a third-party lab, but hospitals, universities, and nursing homes that have labs on-site can process the cartridges within hours, says Thermo Fisher. Scientific. The company also performed “initial feasibility tests” with a rapid PCR test that returns results within 30 minutes. (The test is being performed by Mesa Biotech, which Thermo Fisher Scientific recently acquired.) A series of studies – performed in a closed box, 9-by-14-foot chamber, and hospital rooms of COVID-19 patients – suggested that the AerosolSense sampler could capture the coronavirus even when it is present at low levels, said Kevin Van Den Wymelenberg, who led the research and heads the University’s Center for Biology and Built Environment from Oregon. “We are confident that this is sensitive enough to be used in real world environments with COVID positive individuals,” he said. Thermo Fisher Scientific also piloted the samplers at a COVID-19 field hospital in Worcester, Massachusetts. The hospital deployed the devices to patient care areas, where the virus was supposed to be detected, and to staff rest rooms, where it was not. “Our cold spots were indeed cold,” said Dr. John Broach, emergency physician at UMass Memorial Medical Center and medical director of the field hospital. “And our hot zone was heavily contaminated, which was expected.” Thermo Fisher Scientific, which will focus on hospitals in the first phase of its deployment, says other healthcare facilities could use the samplers to make sure their COVID protocols are working – and that the virus doesn’t come out of patient rooms. “We see institutions questioning whether their planning and screening activities are effective?” said Mark Stevenson, executive vice president and chief operating officer of Thermo Fisher Scientific. “Are their cleaning and ventilation procedures adequate? And therefore, can I give my patients confidence when they visit the facility? Of course, detecting the virus in a COVID-19 patient’s hospital room is one thing, said Alex Huffman, aerosol researcher at the University of Denver: “It’s another step in getting into a environment that probably still has much lower concentrations, monitor a classroom or medical clinic where you don’t know if there will be someone positive or not. And an air sampler isn’t a silver bullet, said Burke, who made sure his firefighters continue to wear masks, socially distance themselves and undergo regular COVID testing even after installing the air sampler. “It can’t be like a smoke detector in your house where you are, like, ‘I’m just going to have the machine, I’m not going to do anything else, that’ll let me know when there’s a problem,'” he said. There are no truly stand-alone viral samplers yet, which still require humans to collect and analyze the samples. This takes time – and means that the results provided by these samplers are not snapshots. real time, but composite portraits of a building in the previous two, 12, or 24 hours. And while PCR analysis can reveal if genetic material from the coronavirus is present, it cannot distinguish between the virus. intact and infectious and viral fragments that pose no risk. None of these drawbacks are a deciding factor, said Marr, who noted that it is always useful to know if airborne coronavirus particles were recently ent in a space. “If they’ve detected it in the air, then it’s probably pretty freshly emitted,” she said. “And I’d be willing to bet there’s an infectious virus in there.” The results should be interpreted with caution. A negative result does not mean that there is no virus present – just that the air sampler did not collect any. “The chances are high for false negatives, because viruses are notoriously low in air,” said Kristen Coleman, bioaerosol expert at Duke-NUS Medical School in Singapore. Understanding how to respond to a positive sample can be even trickier. “I don’t think the answer is just to evacuate the building,” Van Den Wymelenberg said. Instead, he envisioned a suite of more measured responses – from increasing ventilation rates to strategic testing and tracing – that organizations could adopt when they discovered signs of the virus. But convincing office workers that a temporary increase in ventilation allows safe entry into an office where the virus has been found could be a tough sell. And even these modest steps could raise concerns about privacy and legal liability. “I have spoken with several large building owners about monitoring the indoor environment throughout this pandemic, and the question arises of how this information is going to be used and who is responsible for any misapplication of the information. always, ”said Van Den Wymelenberg. (Burke made sure to clear the use of the air sampler with the local unions, who were, he said, “100% supportive.”) Another approach could be to use the air sampler. air for larger-scale surveillance. If public health authorities see an increase in viral levels in a certain region or neighborhood, it could be an early warning sign that an outbreak of new COVID-19 cases is coming – and authorities must step up their testing and contact tracing. Easily available and user-friendly air samplers could also allow more scientists to conduct research on viral aerosols, Huffman said. “In the medium to long term, I think a technology like this has a huge role to play in continuing to advance the state of knowledge on these things so that we can make better decisions that help with others. viral aerosols, like influenza and the next. pandemic that occurs, ”he said. “That doesn’t mean he can’t help now, but I think his real influence could be even greater as we go further and further into the future. This article originally appeared in The New York Times. © 2021 The New York Times Company
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