Despite overwhelming evidence that they don’t work, infrared thermometers continue to be widely used

Feb 3, 2021 | 88 comments

You run into them at the entrances to restaurants, office buildings, grocery stores, airports, gyms and beauty salons and most of us submit to them without a second thought. They are the infrared temperature-taking devices, or guns, designed to keep those infected with Covid-19 virus from entering. The problem, according to experts, is that they are practically useless.

Even though they don’t work, infrared temperature guns have become a mainstay in the fight against Covid-19.

“The information is out there that they don’t work but you still see them everywhere,” says Gil Bedingfield, a public health researcher at Florida State University. “When we read the research news that surface transmission of Covid was only responsible for a fraction of infections – that more than 90 percent of them were the result of airborne transmission — most of us stopped or cut back on our obsessive spraying and washing of things we brought into our homes. For some reason, the research data didn’t stop the use of infrared thermometers as preventive measure against the virus.”

According to Bedingfield and almost every other health officer or researcher who has studied the effectiveness of infrared temperature-taking, the devices used only record the surface skin temperature, not core body temperature. In other words, they don’t show whether you have a fever or not.

“About their only practical use is for plastic surgeons and dermatologists checking the health of skin grafts and various skin conditions. They aren’t checking to see if you are sick or not.”

Even more troubling about infrared devices is that they don’t even accurately record surface temperatures. “Tests on the most popular temperature guns show their readings of the same surface can vary by as much as three degrees Celsius or five degrees Fahrenheit. “More expensive models are slightly more accurate but not by a lot,” says Bedingfield.

“And then you have the millions and millions of them that were rushed to the market to the meet demand. It was another case of operation warp speed, since they were fairly rare before the pandemic,” he says. “Most of the new ones should go straight into the trash.”

Even if thermal guns could check core body temperatures, they would still be ineffective in detecting Covid infections. “The vast majority of people infected with Covid, over 85 percent, have no fever at all,” says Alice Rymner, a healthcare consultant for New York’s Mount Sinai Hospital. “The majority of Covid patients admitted to hospitals do not have a fever,” she says, adding that fever is only one of many symptoms of Covid victims.

Thermal temperature guns and cameras were introduced at world airports at the outbreak of the Severe Acute Respiratory Syndrome (SARS) pandemic in 2002. They were also widespread in airports during the 2009 Influenza A (H1N1) pandemic and medical researchers quickly found they were ineffective in stopping viral spread. In one case, in fact, they found that only 930 potentially infected people were detected by thermal screening from over nine million passengers entering Japan in 2010. As it turned out, not one of 930 had the H1N1 influenza.

So why do the infrared temperature checks remain popular in face of the evidence that they don’t work. “Part of it is that it makes businesses feel like they are doing something to protect people against the virus. People feel helpless in the face of the pandemic and think they have to do something — anything — even if it is mostly symbolic, to fight it,” Bedingfield says.

He adds: “There’s also an economic factor. Some folks are making a killing on these devices and they want to keep the good times rolling.”