The New York Times
The next trick: taking the coronavirus out of the air
A decade ago, when firefighter John Burke completed his master’s degree in emergency health 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 manual ready to go,” said Burke. Testing the virus was a priority, so he connected to a private laboratory to ensure that his firefighters, who were transporting coronavirus patients to hospitals, could be tested regularly. Sign up for the New York Times newsletter The Morning And then he heard that Thermo Fisher Scientific, a Massachusetts company that makes laboratory equipment and supplies, was testing an air sampler that could help it detect coronavirus particles carried by the air. In December, he installed one in the corridor of the fire station. The device, the size of a toaster, sucked in ambient air and trapped airborne virus particles – if there were any – in a specialized cartridge. Every afternoon, an employee removed the cartridge and took it to the UPS collection box across the street, sending it for laboratory analysis. Before the end of the month, the air sampler detected traces of the virus. The authorities ended up discovering a city official who worked at the station, without a mask, during a quiet vacation. It was proof of concept for Thermo Fisher Scientific’s AerosolSense Sampler, which the company was making publicly available on Wednesday. The device, says the company, can be used to detect a variety of airborne pathogens, including the coronavirus. It can be deployed in hospitals, offices, schools and other buildings to monitor for signs of the virus when society begins to reopen. AerosolSense, which will sell for $ 4,995, is not the first air sampler capable of capturing the coronavirus; scientists used several other models to study the pathogen in the past year. But the new device appears to be simpler and more affordable, experts say. “I’m not sure if there is anything else on the market that is so easy to use,” said Linsey Marr, an expert on airborne viruses at Virginia Tech. “This will allow air samples to be taken by almost anyone.” Thermo Fisher Scientific is likely to face competition. The pandemic galvanized interest in an area that was once a disease surveillance niche – taking pathogens out of the air. Experts in the field say they have been inundated with calls and emails from companies, organizations and other laboratories interested in developing or using air samplers to collect coronaviruses. (Marr is consulting with a company, whose name she was unable to reveal, to develop an air sampler that would monitor the virus in public places.) And in November, the Defense Advanced Research Projects Agency began requesting research proposals to develop a coronavirus – air sensor detection. “There is tremendous 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 carefully, with a clear understanding of what technology can and cannot do. Air samplers are already widely used to detect a variety of pollutants. But catching airborne viruses is considerably more difficult. Viral aerosols are tiny and make up only a small fraction of the debris that floats in the air. “You are looking for a needle in a haystack in a field of haystacks,” said Marr. This means that most air samplers need to inhale a lot of air to catch bits of virus, and even then, they may not catch viruses present at low levels. The technology is improving, experts say, but it remains complicated and laborious. “There are very few places that have the knowledge, equipment and virology skills to do this correctly,” said Lednicky. The AerosolSense sampler is designed to be easy to use. The device pulls air into a collection tube and directs it to a replaceable cylindrical cartridge. The cartridge, which is about the size of a 10-milliliter syringe, contains a 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 underlying the gold standard test for COVID-19, to determine whether coronavirus genetic material is present. It may take a day or two to receive the results if the cartridge needs to be sent to a third-party laboratory, but hospitals, universities and nursing homes that have laboratories on site can process the cartridges in a few hours, says Thermo Fisher Scientific. The company also conducted an “initial feasibility test” with a rapid PCR test that returns results within 30 minutes. (The test is done by Mesa Biotech, which Thermo Fisher Scientific recently acquired.) A series of studies – conducted in a closed box, a 9 by 14 foot room and COVID-19 patient hospital rooms – suggested that the O AerosolSense sampler can capture coronavirus even when present at low levels, said Kevin Van Den Wymelenberg, who conducted the research and runs the Center for Biology and Built Environment at the University of 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 implanted the devices in the patient care areas, where the virus was expected, and in the team’s rest rooms, where it was not. “Our cold zones were really cold,” said Dr. John Broach, an emergency physician at the 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 their deployment, says other health facilities could use the samplers to make sure their COVID protocols are working – and that the virus is not coming out of patients’ rooms. “We see facilities asking themselves: are their programming and pre-screening activities effective?” said Mark Stevenson, executive vice president and chief operating officer, Thermo Fisher Scientific. “Are the cleaning and ventilation procedures adequate? And, therefore, can I give my patients confidence in their visit to the health center? “Of course, detecting the virus in a COVID-19 patient’s hospital room is one thing,” said Alex Huffman, an aerosol scientist at the University of Denver: “It’s another step into an environment that is likely to have even more concentrations. casualties, watch a classroom or medical clinic where you have no idea if there will be someone positive or not. “And an air sampler is not a silver bullet, said Burke, who ensured that his firefighters would continue to wear masks, distance themselves socially and do regular COVID tests 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, he’ll let me know when there’s a problem,'” he said. truly autonomous viral samplers, which still require humans to remove and analyze the samples. This takes time – and means that the results provided by these samplers are not snapshots in real time, but composite portraits of a building in the previous two or 12 or 24 hours And although PCR analysis can reveal whether coronavirus genetic material is present, it cannot distinguish between intact infectious viruses and viral fragments that are not at risk. None of these disadvantages is a problem, said Marr, who noted that it was still useful. to know if airborne coronavirus particles were in space recently. “If they detected it in the air, then it was probably emitted recently,” she said. us infectious there. ” The results need to be interpreted carefully. A negative result does not mean that there are no viruses present – simply that the air sampler has not collected any. “There is a high chance of false negatives, because the viruses are in notoriously low concentrations in the air,” said Kristen Coleman, a bioaerosol specialist at Duke-NUS Medical School in Singapore. Finding out how to respond to a positive sample can be even more complicated. “I don’t think the answer is just to evacuate the building,” said Van Den Wymelenberg. In addition, he envisioned a more measured set of responses – from increasing ventilation rates to strategic testing and tracking – that organizations could adopt when finding signs of the virus, but convincing office workers that a temporary increase in ventilation makes it safe to enter. in an office where the virus was found can be difficult to sell. And even these modest measures can raise concerns about privacy. age and legal responsibility. “I have been talking to several large building owners about internal environmental surveillance during this pandemic, and the question of how this information will be used and who is responsible for any misapplication of the information always arises,” said Van Den Wymelenberg. (Burke made sure to release the use of the air sampler with local unions, which were, he said, “100% supportive.”) Another approach may be to use air sampling for large-scale surveillance. If public health officials see an increase in viral levels in a particular region or neighborhood, this could be a warning sign that an increase in new COVID-19 cases is coming – and that authorities need to intensify their testing and screening of contact. Easily available, friendly air samplers may also allow more scientists to conduct research on viral aerosols, said Huffman. “In the medium and long term, I think a technology like this has a tremendous role to play in continuing to boost the state of knowledge about these things, so that we can make better decisions that help with other viral aerosols, like flu and the next pandemic that arises, ”he said. “This does not mean that I cannot help now, but I think that its real influence may be even greater as we move further and further into the future.” This article was originally published in The New York Times. © 2021 The New York Times Company