With the arrival of SARS in Feb 2003, a number of countries introduced infrared thermal screening in airports. A study undertaken by the School of Medicine, James Cook University in Cairns in 2010, concluded that this technique could help identify passengers arriving into the country that have any one of a number of temperature elevating conditions. The passengers could then be subsequently investigated and the cause of the elevated temperature can be determined.
Figure 1. Visual demonstration of thermal camera output (copyright Jay CCTV Solutions (JCS) Ltd)
Seventeen years later the technology and its utilisation has been refined and the accuracy increased. Sophisticated image recognition techniques have been used and it is possible to simultaneously monitor numerous individuals entering a building with or without face coverings and to recognise if their temperature is outside of the normal. Numerous measures and techniques are sued to identify false positive or negative readings and anecdotal evidence suggests that the people who regularly use this system feel safer.
Along with many of the other measures thermal screening could be utilised to help our population move safely indoors to continue with their daily lives as we approach winter in the northern hemisphere.
Using the Swiss cheese model, figure 2, we can see that thermal screening only forms part of the potential protection measures that individuals and organisations need to take to help detect the virus before it has a chance to reproduce. The government guidelines originally had the technique in their portfolio but as things were simplified it was removed. At the beginning of the outbreak in the UK, other measures, handwashing, lockdown, masks, etc., were having a much greater impact so this was a reasonable stance. The WHO however still retains the technique in their guidelines with the caveat that is will not detect COVID-19 but it will help to detect people with elevated temperatures.
Figure 2. Swiss cheese model to combat COVID-19 propagation
A pragmatic approach is if a person has an elevated temperature they should make sure that they are free from any communicable illness. The prevention of transmission of infection from one person to another can be assisted by identifying whether or not they have a fever. Whether the transmission of influenza or COVID-19 is prevented society will benefit and people with symptoms might be discouraged from circulating.
Mark Jackson