John Snell: Monitoring for fever in public places

Editor’s note: This commentary is by John Snell, of Montpelier, who founded The Snell Group in 1985 to train people to more fully use infrared technology in industry. He serves on various city and civic committees and study groups, and was recognized as Citizen of the Year by the Montpelier Rotary in 2015.

We are seeing more and more monitoring of facial temperatures using noncontact temperature devices. In public places, this can be one means of helping control the spread of Covid-19. The purpose of screening people for fever is to identify sick people so they can get proper care and before they infect others.

I was fortunate to have a career of over 30 years using many of these devices for various applications, including medical applications. During the SARS pandemic, I worked with a team of international health professionals to write the standards for using this technology for fever detection. Given my background, I have concerns, especially now that schools and colleges are reopening, and people are traveling more, about how often these devices are being used in a less than effective manner.

Even if we are aided by the technology of noncontact temperature devices, basic commonsense strategies are still the most important, first line of defense: If you don’t feel well, stay home. If you are in public, wear a cloth mask. Simply washing our hands regularly and carefully is still essential to slowing the spread of disease. No fancy monitoring systems are needed to find people who fail to follow these highly effective, basic commonsense strategies.

As important as the strategy is, monitoring facial temperatures for fever is only one part of maintaining health. These devices are very sensitive but will miss detecting numerous people who have the virus and, for whatever reason, do not have a fever. The devices are also very often not used as intended or are the wrong device for this specialized task, so results are not reliable. And no matter what, users need to be trained if results are to be accurate. That said, the technology, despite the recent negative review by Dr. Anthony Fauci, can be an effective part of a larger strategy to reduce the spread of the virus.

Two recent examples are useful to look at more closely. First, Central Vermont Medical Center recently had installed a system that quickly checks people as they walk by a thermal camera. The system and the installation are both very well-designed and, based on my brief observation, meet the intent of the international standards. I have no doubt, if properly maintained, it will detect anyone who has a fever so that appropriate secondary screening can take place. We will see more of these automated systems used where high volumes of people need to be monitored, and they will be an important part of keeping this virus under control.

A second system I saw recently, a small handheld temperature “gun,” is now commonly and widely used because they are inexpensive and seemingly easy to us; also, unfortunately, they are very easy to misuse. These devices typically measure temperatures of a small area on the forehead and must be used no farther away than several inches, a distance that does not respect the need for social distancing. If the device is designed for fever detection and is used and maintained correctly, it may be a good option in many instances. The wrong device, however, or any of them used incorrectly, gives no guarantee a fever will be detected and could, in fact, yield many false positives or false negatives. Further, if it is used and then handed from person to person without being cleaned after each use, it can quickly become a vector for transmission of the virus.

The need for fever detection will be with us for a long while. We must invest for the long term, as well as for the maintenance of any systems and, importantly, continually training and upgrading the best practice procedures for their use. Schools will monitor not only children and teachers but, at some point, the public attending a school board meeting or a basketball game. The need for effective, accurate fever detection at stores, museums, city halls and the Statehouse will be with us for a long time. We need to make sure monitoring is done correctly and continues to be done accurately.

Fever detection is important, but only if it is part of a larger system of proven public health practices and only if it is done properly. We cannot afford to be lured into thinking these “high-tech” tools alone will save us from Covid-19 and, if they are destined to play a role in this battle, they must be used correctly.

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