How Effective Are Thermal Scanners For Detecting COVID-19?

By Ellen Kershner on May 28 2020 in Society

A woman being checked for fever using a thermal scanner. Image credit: Mongkolchon Akesin/Shutterstock.com
A woman being checked for fever using a thermal scanner. Image credit: Mongkolchon Akesin/Shutterstock.com
  • fever is a main symptom of the coronavirus
  • Infrared cameras and thermometers and cameras do detect fevers accurately by using sensors that read infrared light.
  • COVID-19’s incubation period also takes up to 14 days from infection point to symptoms showing,
  • FDA guidelines specify that they are not intended for medical purposes.

As we all know by now, fever is a main symptom of the coronavirus, and daily temperature checks with infrared cameras have become routine for businesses, their employees, and other public places. The Centers for Disease Control and Prevention (CDC) and Food and Drug Administration (FDA) have weighed in, stating that health care providers, assisted living facilities, and workplaces can consider using temperature checks. In April, the FDA relaxed regulations on the cameras, to increase the scope of their technology. The remaining question is, though, do the cameras accurately detect COVID-19?

How They Work

A close-up view of a thermal scanner. Image credit: Suntorn Somtong

Large companies like Amazon and smaller ones have been sending workers through temperature checkpoints as a tool to prevent the virus from spreading. In fact, Amazon claimed that these checks detected staff members who had fevers and later tested positive.

Infrared cameras and thermometers and cameras do detect fevers accurately by using sensors that read infrared light. This produces wavelengths, which correspond to varying temperatures. The thermometers are able to read a temperature on a single part of someone’s skin. This is usually done by aiming at a person’s forehead from about six inches away.

Not Foolproof

University of California Los Angeles Professor Jamie Lloyd-Smith stated that screening for fever and symptoms is not foolproof. Her February study showed that these screenings would “miss more than half of infected people,” adding that the virus can be spread by people even if they pass the screenings.

COVID-19’s incubation period also takes up to 14 days from infection point to symptoms showing, and during these two weeks it is still possible to transmit the virus. Further, people who have fevers and take medication like acetaminophen can slip by temperature checks.

Sales Are Up

Kuala Lumpur,20 March 2020-Malaysia.A police officer screening body temperature of a visitor using an infrared thermometer amid the pandemic. Image credit: YuriAbas/Shutterstock.com

As organizations and businesses first scrambled to buy the infrared cameras, some may have been spending too much. In Georgia, officials from Gwinnett County agreed to purchase four “fever detector” scanners manufactured by RedSpeed USA, which sells red-light traffic cameras. Each came with a price tag of $30,000.

Other companies have hopped on this bandwagon as well, including FLIR Systems. They manufacture their own sensors and thermal cameras, which other companies buy and use in their products. FLIR saw increased sales during the Ebola, SARS, and swine flu outbreaks. According to the Director for Global Business Development Chris Bainter, the current spike in sales from COVID-19 is “the biggest yet.”

The Facts

Even though these cameras are being used often, FDA guidelines specify that they are not intended for medical purposes. Although they can be marketed for non-medical purposes like industrial applications and construction, they are not supposed to be used to diagnose diseases and other conditions. In addition, they are not intended to be used for disease prevention, treatment, mitigation, or cure.

These scanners are considered to be devices. When marketed for non-medical use, FDA does not require device marketing authorization. However, they are taking steps to expand availability to address coronavirus health concerns.

A Wired.com article describes a review that studied 15 years of data from international border screenings. These checked for symptoms like fever and coughing. The data showed to be ineffective for detecting cases during Ebola, SARS, and swine flue outbreaks.

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