COVID-19: Don’t Believe the Hype for Thermal Imaging Temperature Screening

Thermal imaging cameras are flying off the shelves as companies buy into the promise that they can provide a rapid means of detecting people showing symptoms of COVID-19 without the need for physical contact.

But do these devices live up to their claims? And if they do, are they enough to make workplaces safe?

Thermal imaging has many uses – detecting COVID-19 isn’t one

Thermal imaging cameras are a valuable tool used by firefighters, police and security companies such as ourselves but they do not have any approved medical uses.

While they are effective at detecting broad ranges of temperature, they are not precise enough to accurately identify an individual with a fever. Most are accurate to 0.5 degrees celsius, which may sound impressive on paper, until you consider that the difference between normal body temperature and a fever is just one degree celsius.

But accuracy is not the only limitation. A fever is diagnosed by recording the internal temperature of the body, while thermal imaging cameras only detect skin temperature, which can vary significantly for any number of reasons not related to a fever.

Not only is thermal imaging not an accurate means of detecting a fever, it is particularly unreliable for detecting COVID-19.

A fever is just one of many symptoms that might be presented by someone carrying COVID-19 and many people will present none at all. A fever might also be caused by a far more common illness, such as a cold.

This means that both false positives and false negatives are very likely when using thermal imaging or any form of temperature readings as a means of detecting COVID-19.

COVID-19 cannot be managed through detection alone

Even if thermal imaging was 100% effective, COVID-19 cannot be prevented or controlled through detection alone due to its wide range of symptoms (with many carriers reporting none at all) and long incubation period.

Businesses continuing to operate sites during the pandemic must work under the assumption that everyone potentially carries the virus. We have written at length about how work can be carried out as safely as possible during the pandemic, but the key points are:

Anyone hoping for thermal imaging cameras to be a magic bullet that prevents the need for the above will not only be disappointed, they will put their staff and wider communities at risk of infection.

COVID-19 outbreaks in the food industry show failings of thermal imaging

A recent high profile example of the limitations of thermal imaging comes from the the 2 Sisters Food Group meat factory in Anglesey Wales, where over 200 confirmed cases of COVID-19 were reported – making it one of the largest industrial outbreaks in the UK.

Thermal imaging cameras had been installed in the factory prior to the outbreak which clearly proved to be an inadequate measure. While 2 Sisters Food Group stated that they had put many other safety measures in place, staff told the press they believe lax shift patterns were to blame.

The factory has since temporarily closed, and 2 Sisters Food Group have promised that workers on the production line will be separated by protective screens.

This was not the only meat factory to suffer an outbreak. A Kober Ltd site in West Yorkshire saw 165 confirmed cases despite implementing temperature checks (the method for which is unknown, but thermal imaging is likely).

Unlike the Anglesey site, the Kober Ltd plant did not shut down. Workers talking to the press shared concerns that social distancing measures had not been adequately enforced and that there was no deliberate staggering of shift times.

As the site remained open, workers would instead have to rely on £94 per week statutory sick pay if they took time off. This increases risk in the workplace, as people in low pay positions with precarious job security are unlikely to report their symptoms or take time off as they simply cannot afford to.

There are no shortcuts to preventing and controlling COVID-19

At Magenta Security, we are very concerned by the growing popularity of thermal imaging as a part of COVID-19 mitigation strategies. At best, they are a waste of resources that could be better allocated and at worst, they might lead to a false sense of security and complacency.

Making a workplace safe during the pandemic is difficult but opting for shortcuts in the name of convenience is only going to drag out this already devastating pandemic. We urge companies to do the right thing and follow the steps outlined in the bullet points above.

If you need any help fortifying your workplace against coronavirus, we offer a COVID-19 risk assessment that is constantly updated to the latest guidelines and research, carried out by trained security professionals.

To book your COVID-19 risk assessment or discuss your businesses security needs call us now on 0800 772 3786.


Magenta Security provide award winning security services throughout the UK. We are in the top 5% of ACS approved contractors and were the first security company in Europe to be awarded ISO 14001 for our environmental management systems.

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