The US Food and Drug Administration (FDA) has issued a public warning over Covid fever scanners and sent letters to four companies selling the devices, following new research which suggested they were inaccurate.
The Washington Post reported on Thursday that the fever scanners were being used throughout the US to detect possible cases of Covid, at places such as airports and sports stadiums.
But surveillance research body, IPVM, found that seven fever scanners could read temperatures incorrectly — recording a person suffering a feverish 100.4F temperature as an ordinary 98F core temperature.
Responding to the Post’s report, the FDA released a public alert on Thursday which said some scanners could be inaccurate and “present potentially serious public health risks”.
Four companies were sent warning letters from the FDA for selling devices that were portrayed as fever scanners for Covid, and were asked to cease trading the products.
The companies were Certify Global Inc., Kogniz Inc., Opgal Optronic Industries Ltd. and Thermavis.
In the letter to one UK-based company, Thermavis, the FDA said a “Thermal Screening Camera” sold online in the US was “without marketing approval, clearance, or authorisation from FDA”.
The letter added that thermal screening devices risked “incorrectly detecting a normal human body temperature” and that such inaccuracies were more present when scanning “multiple individuals simultaneously”.
Representatives for four of the firms in the IPVM study told the Post that the devices contain software which allows them to “self-calibrate” to their environments, and disputed claims of inaccuracy.
A researcher on thermology, Peter Plassmann, said that such devices proved some companies were overselling the capabilities of fever scanners for detecting Covid.
“That’s generally the problem with infrared imaging: It’s so deceptively easy,” said Mr Plassmann. “You point the camera at somebody, you get a nice colourful image and you get a temperature reading. Great. But in reality, it’s all rubbish. There are so many factors you need to consider.”
IPVM found that over 200 firms started selling thermal scanners for Covid following a decision by the FDA in April to cease testing and reviewing devices “that did not ‘create an undue risk’, due to the public health emergency.
According to studies by the Centers for Disease Control and Prevention, roughly 40 per cent of those infected with coronavirus will not have a fever — meaning the use of fever scanners is ineffective, reported The Post.
The Independent has approached all four companies who received FDA warning letters for comment.