Dr Yousuf Ali Al mulla
We have noticed an increase in installation of thermal imaging cameras in various public places after coronavirus outbreak, to check the health status of individuals entering commercial centres.
The use of infrared technology to detect the heat radiated by the human body has increased. However, it is not easy to get an accurate reading of body temperature, as the normal temperature varies from person to person and changes during the day and also it experiences fluctuations during a woman’s menstrual cycle, for instance!
However, we all have heard that there are people infected with coronavirus, but they are not showing any symptoms at all. While fever is one of the most common symptoms of people who get sick, it is still far away to be a symptom of all infected people. Many of the cases that were diagnosed with coronavirus were mild cases and fever was not the main symptom in them and I may say here that using fever sometimes as a tool to check COVID-19 may create a false sense of safety!
Nevertheless, is there any concern about using such an infrared temperature test, for example? Knowing that anything that can benefit our health, also has the potential to undermine it. For instance, if people are reassured after checking temperature and become complacent in wearing face masks, maintaining physical distancing and washing hands, they put themselves and others at risk. And therefore, perhaps this test does not have the ability to reassure people, but it has a real ability to deceive, if I can say that.
Indeed, this leads us to understand that a useful test must be sensitive and specific. The test, in order to be medically sensitive, must capture most cases (preferably all cases) while the test is specific if it does not misidentify a very large number of cases. In other words, especially with the use of such a test as infrared thermometers, we must be aware of where and how to use it. Therefore, a person can appear with a temperature above average because he has just gone out for a run or during anxiety. Also, when we sweat our body expels heat through the skin. Here, I think if you agree with me, that there are people who take medicine to hide the fever and therefore even if the infrared thermometer was done correctly at entry to a mall or commercial center for instance, checking the temperature is not necessarily sufficient to determine the cases and here also lies the problem!
Of course, many restaurants and hotels use an infrared thermometer to return to the business during this pandemic, but my question here is where is the scientific and real evidence that such a test for body temperature is a useful intervention? Are these temperature devices accurate or is it purely commercial marketing? In addition, unfortunately and unusually one of the medicines and medical products agencies known worldwide has issued a statement in the past months, stating that thermal cameras with infrared thermometer and other (temperature-checking) products that are provided for testing COVID- 19 are not a reliable way to test whether people are infected with the virus. This really leads me to ask: Do temperature readings from temperature screening systems measure skin temperature instead of core body temperature?
On the other hand, infrared scanners are inadequate in measuring sublingual or rectal temperature. Most importantly, when these devices are aimed at your forehead, we may trust the result. Yet if you imagine scanning a group of people, as some major recreational centers have begun, the accuracy is unfortunately fading. Not to mention that infrared thermometers, for example are designed similar to thermal cameras to detect life in the field and for industrial or military uses , not to assess individual fevers. It measures skin temperature, rather than core temperature, which undoubtedly can be affected by cosmetics or fever reducers. It appears that it has an uncertain relationship with the core temperature of the body. Consequently, infrared temperature checks lead to large numbers of false positives, which could end up providing false reassurances or unnecessary alarms and possible exclusion of a person from work or their personal and recreational activities.
Of course, checking the temperature may be useful in specific circumstances, especially with symptoms of fever and cough, for example and thus accessing the appropriate testing procedure to verify their infection with the virus and seeking medical attention is required and important in such cases. And by comparison we see that people can be infected with either stage pre-symptomatic or completely asymptomatic. Thus, perhaps by the nature of an infrared thermometer, we may risk public embarrassment and confidentiality when using it in a group setting. Here, I believe that the best way to protect customers of malls, hotels and other institutions or centers, is to reduce the risk of infection with the virus, by always following social distancing guidelines, wearing face masks in public and closed places, and washing hands regularly.
At the end, even if the temperature test, as mentioned above is done correctly, the routine temperature checks that we see in the market are not necessarily sufficient to determine the correct cases of coronavirus, but rather the fever tests may give us a false sense of safety and will do more harm than good!
The writer is a physician, medical innovator & writer.
