How accurate are tests to detect coronavirus on surfaces? | Innovation

Even before California went on the block thanks to the COVID-19 pandemic, MacKenzie Smith, the chief librarian of the University of California, Davis, was worried. The approximately 400,000 square meters of library space he supervises is full of books and other constantly changing hands – and could help spread SARS-CoV-2, the coronavirus that causes COVID-19.

Smith and his colleagues wanted to know if they had to implement self-monitoring stations, quarantine books on return and speed up their cleaning and disinfection efforts. “There are a million questions,” he says. And there are no official guidelines. So together with Jonathan Eisen, an evolutionist biologist at UC Davis who studies how viruses and other microbes interact with their environments, Smith began working on his guidelines, drawing up a plan for testing surfaces such as desks, handles and books.

And while corporate giants like them Amazon is Smithfield Foods as they rush to develop new safety and testing procedures in response to serious outbreaks in their facilities, Smith’s concerns echo the concerns of people who manage relatively smaller spaces across the country, including building administrators, teachers, restaurateurs and hoteliers.

Centers for disease control and prevention He says it may be possible for people to contract COVID-19 by touching contaminated surfaces or objects and then touching their mouth, nose or even eyes, although many experts do not think this is the main way in which coronavirus is spread. As more states and cities lift home orders and reopen multiple companies, campuses and public spaces, how can we be sure that they are not hiding infectious traces of coronaviruses?

Without official protocols for monitoring public spaces, several academic laboratories and private companies are working on tests – some in the research stages and others that are already offered for sale, sometimes at high prices.

But while scientists can focus on how and where the virus spread, the people who run businesses and other organizations want to know if the spaces they manage and use are safe on a daily basis. That basic question doesn’t have an easy answer, because testing viral presence on surfaces is far from simple. The tests vary widely; they can be very expensive, take days to get results, and provide only a limited amount of useful information, if any. Despite the uncertainty, some organizations are already looking into the possibility of performing such tests, even if it’s just for peace of mind.

The biggest obstacle to testing is to be able to distinguish a “live” virus, which can infect a person, and traces of viral RNA, the genetic material that the virus leaves as it degrades, which cannot harm anyone. And while scientists have the tools to distinguish between the two, that level of analysis will not be available to the average merchant or restaurant owner. “It will be a great challenge,” says Andrea Silverman, who studies urban engineering and public health at the Tandon School of Engineering at New York University and the College of Global Public Health. “Detecting RNA doesn’t necessarily mean you have an infectious virus.”

Viruses can linger on surfaces, from bar counters to fountains to bathroom sinks, and coronavirus is no exception. For example, preliminary research published in the New England Journal of Medicine in April, he suggests that viable coronavirus can remain on plastic and stainless steel for 72 hours, cardboard for 24 hours and copper for four hours. Search in The Lancet published in the same period he discovered that the infectious virus survived on the outer layer of a surgical mask for a week.

To delve into the longevity of the coronavirus, both research teams buffered various surfaces to collect potential particles and developed the virus in the laboratory inside the host cells. “This is the gold standard,” says Silverman – if viruses can multiply and grow inside cells, they are contagious.

But the growing viruses that can afflict humans can be dangerous and require structures with extensive safety features – called biosafety level 3 labs – in which scientists wear suits against the risk to the body. other protective devices. These tests require highly qualified personnel and specialized equipment, therefore biosecurity laboratories are mainly located in research institutes, which daily companies cannot easily access. “The labs that are growing cells for SARS-CoV-2 are very busy,” says Silverman, “They don’t have the bandwidth for many samples from people in the community.” And given their specialized nature, such tests would likely be too expensive for the average company.

For more accessible tests, most people have to resort to the next best thing: check for viral RNA. This requires machines that use a process called polymerase chain reaction (PCR), which makes many copies of small fragments of genetic material to facilitate testing that can identify where it comes from. But since this test cannot say for sure if the test area contains infectious viruses or only traces of its genetic material, this approach can lead to false positives, says Eisen.

“Even if you detect RNA, you don’t know if your virus is still” alive “on the surface or not,” says Silverman. “And this affects the fact that this environment is safe from quotes.” For librarians like Smith, viral RNA tests won’t show if his books have infectious traces of the virus on them. Restaurateurs who want to know if their tables are safe to seat customers for dinner will not even receive a clear answer.

This does not mean that viral RNA tests are unnecessary: ​​they are only more suitable for epidemiological studies, says Eisen. For example, tests could show how the virus spreads and detect hotspots.

This could help identify super shedders: patients who vomit more viruses than others, says Jack Gilbert, a professor of pediatrics at the University of California, San Diego, who studies how microbes travel and has tried local hospitals to investigate what makes one a super shedder. “We want to determine the variance in patients: how much RNA they leave in a room,” he says.

Scientists can also build the coronavirus family tree by analyzing viral RNA from different locations. As viruses turn into new strains, their RNA changes, so scientists can find their place on the family tree and understand where a particular version of the virus comes from.

Tracking mutations can even reveal whether employees have collected the virus at work or elsewhere, says Eisen. His team is starting to work on this in hospitals, he adds “to understand if health workers are picking it up from hospitals or the community.” That nuance is the key to some employees who get COVID-19 – when they are infected on the job, they qualify for workers’ compensation payments.

But testing the surfaces people come in contact with for viral RNA has some value, says Eisen. Similar to how health workers test public beaches for harmful bacteria, some common areas can benefit from coronavirus monitoring. For example, if an office kitchen that didn’t have traces of coronavirus last week suddenly shows large quantities, someone who is using the kitchen is infected. So the traces of the suspended ceiling can be informative. “You still don’t know if you have a” live “virus or not,” says Silverman. “But at least you have the feeling of what happened in your space, whether the organism was introduced.”

Several academic research groups and companies are already testing surfaces for coronavirus. In addition to the studies conducted by Eisen and Gilbert, researchers from Weill Cornell Medicine in New York I looked for the potential spread of coronavirus in the New York City subway system. For a week before the city went into lockdown, Weill Cornell’s geneticist Christopher Mason and his team dabbed handrails, kiosks and floors at Grand Central and Times Square stations, two of the busiest in the city. The researchers then tried different types of tests to detect the virus. Surprisingly, the 86 samples collected did not appear to contain viable coronavirus.

But Mason’s experiments may have coincided extensive cleaning efforts by the Metropolitan Transit Authority, the entity that manages the subway, which may have swept away the traces of the virus.

Despite the uncertainty of viral RNA testing, some companies are already offering services for high-traffic areas inside buildings. “Some companies may have risk management teams or insurance companies that will request them to test,” says Dan Ventura, owner of Hawk Environmental Services in Seattle, who tests a variety of dangers from mold to bacteria to asbestos and recently added coronavirus to the list. Ventura says that if several employees fall ill, managers may want to thoroughly clean the facility and then use the tests to prove that there is no detectable viral RNA. Others may speed up their cleaning procedures after finding RNA where it has never been before. The tests, he adds, “will allow these buildings to remain open, operate and provide a second level of security.”

But tests can take several days to process, which could make the results questionable, says Gilbert, and by then people may have already been infected. “Why not simply increase cleaning procedures?” Adds.

To reduce waiting times, Ventura offers accelerated tests at a price. Hawk will ship swab kits to customers, who will then go to a third-party lab. (Ventura declined to name the lab, citing concern that he would be inundated with requests and suffer from bottlenecks.) The cost it ranges from $ 365 per swab with a four-day turnaround to $ 605 per swab for a 24-hour turnaround – the prices Ventura says are “affordable when viewed through the goal of accountability for the operation.”

How many swabs are needed is unclear and there are no clear guidelines. Ventura says it leaves companies the decision on how many to use and the size of the sampling areas. In academic laboratories, the appropriate number of swabs also varies, as scientists define their methods of meeting specific research goals. Silverman cites an example of a non-coronavirus in which his team used a swab for about a square meter of surface, but other researchers could do things differently. “It is not entirely clear how it would translate into a cafeteria,” he says, but a shopkeeper will still need more swabs because “it is not possible to use one swab for each surface.”

Testing viral RNA in a university laboratory, especially in large batches, is significantly cheaper. “The raw cost per sample is probably ten dollars,” says Eisen. However, Ventura claims to receive up to 10 calls per day from companies potentially interested in the tests.

Other companies are offering coronavirus testing equipment, including Aanika Biosciences in Brooklyn. Aanika is developing a way for companies to trace and authenticate their supply chains by labeling products with a harmless microbe, which can act as a biological barcode. To detect microbial DNA, Aanika uses chemical methods and equipment that can also be used to detect coronavirus RNA, says biologist Ellen Jorgensen, the company’s scientific director.

In March, Jorgensen called New York City officials to offer assistance in testing coronavirus in buildings. The company’s prices aren’t set yet, but Jorgensen also offered to take free tests for New York schools. So far the city has only sent her one form to fill out and has heard nothing else. “Over time I could try again,” he says.

ChaiBio, a biotechnology company from Santa Clara, California, sells test equipment directly to companies, thus eliminating long waits for test results. Traditional PCR machines used in research labs may cost $ 200,000, but ChaiBio sells versions for less than $ 10,000. Originally developed for the food industry, the machines are used by brewers to detect bacteria that spoil beer.

When COVID-19 arrived, ChaiBio developed a process to test the new coronavirus. An initial package for the virus costs $ 8,500 and includes the machine, swabs and other test materials. Using the ChaiBio machine does not require a biology degree and takes less than an hour, says CEO and co-founder Josh Perfetto. Unlike traditional PCR machines, which search for the entire RNA sequence of the virus, ChaiBio searches for specific genetic pieces only for the organism of interest, which reduces time, complexity and costs. “Put your sample in the device and it gives you the result on the computer screen,” he says.

But the idea of ​​someone without training performing coronavirus tests on their academic concerns like Gilbert, who notes that it still takes some degree of experience to perform these tests, including how to calibrate machines and how to manage samples. The results, he adds, are complex and can be interpreted, another task that could prove difficult for a layman.

The process is “not for an employee or someone at home who wants to hit the door handle,” says Gilbert, because there is too much possibility of error. A safer approach to reopening companies and public areas, he says, is simply to practice social distancing, wear protective clothing such as masks and gloves, and adequate sanitization.

As for the UC Davis library, Smith wants to know if customers and staff can safely move books back and forth once the campus is reopened and if he must purchase UV sanitization equipment, from libraries, with their stacks of books delicate and other materials, cannot be sterilized with aggressive chemicals and steam. So she and Eisen are planning a pilot study, testing the books to determine how quickly the coronavirus decays, how books with different types of covers should be quarantined, and how often caretakers need to clean handles and other surfaces.

“We won’t reopen the space until we understand it,” he says. “Here we are opening a new path.”

Lina Zeldovich is a writer and scientific editor. He wrote for Newsweek, The Atlantic, Smithsonian, Audubon, Nature, Scientific Americanand more.

This article was originally published on Undark. Read the original article.

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