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'Fever detection' cameras to fight coronavirus? Experts say they don't work

"I have many customers approach and say, 'Wow, this is a good thing you do,' and some customers are excited to get their temp taken," one business owner said.
Image: Thermal imaging
A health worker watches arriving passengers via thermal image monitoring at Suvarnabhumi International airport in Bangkok, Thailand, on Jan. 29, 2020.Thai Government Spokesman's office via AP file

In an attempt to protect shoppers and his employees from contracting the coronavirus, Ben Vo, the owner of City Farmers Market, a chain of grocery stores in Georgia, recently set up thermal cameras at the entrances of each of his six locations.

"It’s focused on the face, so basically we measure the head temperature as they walk into the store," Vo said. "It’s in the corner, not right in front of the entrance, and we have an LCD monitor that security personnel can watch and the customers can also see."

If an associate sees a reading that comes in at 100.4 degrees or higher, that shopper is pulled aside and handed a flyer that asks them to leave.

Vo said this has happened only twice in the two weeks since he installed the cameras, which are made by FLiR, a company that specializes in thermal imaging cameras. There has been a dramatic rise in demand for these kind of cameras in recent weeks, even though experts say they are an imprecise tool for identifying people who are infected.

Vo's grocery stores are offering to take customers' shopping lists and retrieve groceries for them if they are asked to leave because of their temperature reading.

"I have many customers approach and say, 'Wow, this is a good thing you do,' and some customers are excited to get their temp taken," Vo said.

Vo isn't the only business owner interested in experimenting with thermal imaging cameras to surveil people's body temperatures as a tactic to mitigate the spread of the coronavirus.

NBC News found more than 10 security companies in the U.S., Europe and China that are marketing technologies as capable of picking out who in a crowd is likely to have a fever, and thus a possible coronavirus case. These companies are actively pitching to police departments, government agencies, schools, hospitals and private businesses.

Image: Thermal imaging
A thermal camera monitor shows the body temperature of passengers as a way to detect COVID-19, as they arrive at Mexico's International airport in Mexico City, on March 18, 2020.Fernando Llano / AP

The idea is that thermal cameras can ferret out sick people in a crowd by finding those who have elevated temperatures, according to 11 surveillance companies NBC News found marketing the technology as a form of coronavirus detection. Fever is a symptom of COVID-19, the disease caused by the coronavirus.

But the problems with this technology, according to thermal imaging and virus surveillance experts, is that thermal imaging is an imprecise method for scanning crowds, and doesn't measure inner-body temperature.

They also noted that the coronavirus only produces a fever after a person is infected for days, if there are symptoms at all. A recent study in Iceland looking at tests from a sizable portion of the population found that 50 percent of everyone who tested positive were asymptomatic.

The rise in demand for thermal cameras also comes as governments are looking for new ways to track who is sick, including turning to smartphone location data.

On Thursday, President Donald Trump wrote in a letter to governors that the federal government plans to implement "robust surveillance testing" in an effort to help assess risks of individual counties for states struggling from businesses and school closings in response to the outbreak, though it's unclear if he was referring to thermal imaging.

A booming market

A range of companies are selling thermal cameras for fever detection. Surveillance tech startups have quickly launched new products and websites to jump on the opportunity to sell high-tech solutions to businesses desperate to get back to work. Other companies have long been in the surveillance camera market and were selling thermal imaging for years before the coronavirus swept the world.

In a video posted to Twitter, one company, Remark Holdings, pitched its fever surveillance system to the Las Vegas Police Department on Monday.

In the presentation, the company's CEO, Shing Tao, said that with their fever surveillance technology, a customer, such as a law enforcement agency, would be able to point the camera at a large crowd and "be able to identify who they are, match them with a virtual ID, capture their temperature," which, he added, his company has been testing for the past two years.

Remark Holdings also makes facial recognition technology that it claims works even if the target is wearing a mask.

The Las Vegas Police Department did not respond to requests for comments.

Thermal image scanning for fever detection is broadly in use across China and South Korea, where the systems are set up in the fronts of businesses and buildings across both countries. Some U.S. businesses, like Wynn Resorts in Las Vegas and Vo's chain of grocery stores in Georgia, have set up thermal imaging systems, too, but the technology is not yet broadly adopted.

Some American companies are hoping to change that.

Companies that sell cameras for fever detection and surveillance say that demand for their products has skyrocketed. Remark Holdings' Tao said that the interest in his company's fever surveillance technology right now is "massive."

John Honovich, the founder of IPVM, a trade publication that investigates and reviews security cameras, said thermal cameras are "bar-none clearly the hottest selling item in video surveillance right now, and companies are scrambling to get products all over the place."

"The only thing I would compare it to is when I first got into the surveillance camera industry after 9/11 when price was no object," Honvovich said.

One firm, Athena Security, which sells a "fever detection system" has already clocked in more than 1,000 orders in the last two weeks since they launched their new product, the company's CEO, Lisa Falzone, said.

Some companies are combining fever-detection with face recognition and AI-powered sorting of individuals.

One company, Feevr, claims it leverages "AI face detection and thermal imaging to screen people with an elevated temp" in its marketing materials posted to its website,, which was only created at the beginning of the month. The company that owns, X.Labs, makes technology that specializes in weapons detection, which also uses thermal imaging.

"We have sold 5,000 units in the U.S., and we are building more," said Steve McClinton, a vice president of sales at X.Labs, in an email. The company wouldn't share any details about who their customers are, citing privacy concerns.

Athena Security also specialized in gunshot detection before pivoting to fever detection, which the company's CEO said is already being tested in a startup-focused co-working space called Capital Factory in Austin, which is currently closed due to a county-wide shelter-in-place order.

FLiR, a well-known security camera company that's been making thermal imaging cameras for body temperature detection cameras since 2002, said that it, too, is seeing a large demand in orders. FLiR's thermal imaging cameras for reading body temperature are approved for use by the Food and Drug Administration, unlike those from Athena Security, Feevr and Remark Holdings.

Image: Grocery shoppers
Customers walk into a store with thermal imaging cameras installed.City Farmer's Market

Athena Security's Falzone said that it don't consider itself a medical device company and therefore isn't seeking FDA approval, though the company claims its thermal scanning technology is accurate at reading a person's body temperature up to a half degree Celsius. Falzone added that their system is intended to be for preliminary screening and should be followed up by another thermometer temperature check.

Remark Holdings' Tao said that their technology is accurate at reading someone's body temperature in a crowd within 0.3 degrees Fahrenheit. Despite claiming such high levels of accuracy, Tao also added that Remark is "hardware agnostic" and customers can use any kind of thermal imaging camera they'd like.

Inaccurate and asymptomatic

Thermal cameras may be able to accurately read a person's skin temperature, but that does not mean they are effective at identifying people who have been infected with the coronavirus.

"The big problem is that not everyone develops a fever. The vast majority of cases are mild to moderate," said Dr. Joseph Fair, a virologist and epidemiologist, referring to COVID-19. "And then we have asymptomatic people as well that are very infectious."

"Temperature checks are things that we mostly do out of an abundance of caution, but they're mostly a visual measure that makes you feel better," Fair said. "It makes you feel like you're going through some kind of screening but they have very limited effectiveness."

Image: Grocery shopper
A customer walks into a grocery store with a thermal imaging camera installed.City Farmer's Market

For screening people's health when traveling, the World Health Organization notes that "temperature screening alone may not be very effective as it may miss travellers incubating the disease or travellers concealing fever during travel, or it may yield false positive (fever of a different cause)," in guidance on its website.

The European Commission also noted in a 2014 presentation that thermal scanning isn't very accurate because it only measures skin temperature and not people's inner body temperature and is affected by changes in the environment.

This hasn't stopped their spread. Thermal camera systems scanning crowds are currently deployed at airports around the world, including in Hungary, Turkey, Mexico, Singapore, Jamaica and Abu Dhabi. A hospital in Dublin has also recently adopted a thermal temperature scanning system.

A false sense of security

With some businesses, like Vo's grocery stores, already embracing thermal cameras, there's some concern the technology may give people the impression that they're safe or healthy when that's not the case.

"People are frantic to get their business back open, so they're trying to figure out anything they can do to get customers to come back or make employees feel safe," Honovich said.

But making people feel safe could provide a false sense of security, Honovich added, especially when the primary advice from public health officials now is for everyone to self-quarantine if possible.

Jay Stanley, a senior policy analyst at the American Civil Liberties Union who specializes in surveillance technologies, said that if these technologies were effective in preventing the spread of the coronavirus, they should be used.

Image: Thermal imaging
A Health Officer uses thermal scanners to monitor the body temperature of passengers at Adisutjipto International Airport in Yogyakarta, Indonesia, on March 5, 2020.Devi Rahman / INA Photo Agency/Sipa USA via AP file

But he cautioned that the ineffectiveness of thermal imaging to identify coronavirus infections combined with the growing use of thermal cameras creates privacy concerns.

"There are privacy questions about measurements of people's metabolic functions, and we don't want to see the world after COVID-19 where we end up with measures that last beyond this crisis and companies feel they have the free hand to go around taking people's temperature all the time," Stanely said.

"It's more important than ever that everybody, including law enforcement, listen to what public health experts are saying about what needs to be done and what is effective and what isn't."