Scientists warn of limitations of Covid-19 temperature screening

Scientists warn of limitations of Covid-19 temperature screening

The National Metrology Laboratory says measurement errors, quality of instruments used, and factors such as inadequate training with temperature measurement tools can lead to inaccurate readings. Picture: File Picture/Denis Boyle

Irish scientists are urging businesses and organisations to be mindful of the limitations of temperature and fever screening as regards the detection of Covid-19.

As the demand for increased Covid-19 screenings intensifies, a new report from the National Metrology Laboratory (NML), which maintains national measurement standards for a range of physical quantities, says that fever and temperature tests should only be used in addition to public health guidelines and advice such as practicing social distancing, hand-washing, and the wearing of face coverings.

While there is currently no public health requirement to undertake temperate tests, many businesses, schools, and other organisations have been using them as part of their protection measures.

However, the NML report outlines several shortcomings related to the use of temperature screening. It says measurement errors, quality of instruments used, and factors such as inadequate training with measurement tools can lead to inaccurate readings.

Dubhaltach Mac Lochlainn, a technical manager specialising in temperature at NML said that temperature screening "may not be an appropriate model of Covid-19 detection for schools, airports, businesses, and other communal spaces."

These day-to-day settings do not have the conditions needed for accurate non-contact thermal screening. 

Mr Mac Lochlainn said: "HIQA have already come to this conclusion from a medical point-of-view, and our report now offers the same opinion from the measurement science perspective.”

Last month, a Health Information and Quality Authority (HIQA) report found a high temperature was not always an indicative symptom of Covid-19, and thus, that thermal screening was often ineffective in limiting the spread of the virus.

The new NML report states that, in addition to fever screening resulting in very low detection rates of Covid-19, factors such as the distance from the subject, angle of measurement, measurement location on the body, and varying environmental conditions can all lead to an inaccurate temperature reading. 

 “The report stresses that non-contact thermal screening is supposed to be carried out by a trained professional in an appropriate clinical setting over a period of time to find temperature variations. 

"Ultimately, taking the technology out of that setting is going to give inaccurate results and therefore shouldn’t be used to make a diagnosis of an individual,” Mr Mac Lochlainn added.

The Irish Travel Agents Association is calling for Covid-19 temperature tests to be routinely carried out on passengers boarding flights out of Ireland, as an alternative to quarantine measures upon arrival at their destination.

The ITAA believes the measure would help reduce the risk of transmissions, while also helping facilitate the return of air travel generally.

 The Irish Travel Agents Association is calling for Covid-19 screening should be carried out on passengers leaving Ireland, rather than on passengers arriving at their destination. Picture: Colin Keegan/Collins Dublin
The Irish Travel Agents Association is calling for Covid-19 screening should be carried out on passengers leaving Ireland, rather than on passengers arriving at their destination. Picture: Colin Keegan/Collins Dublin

The ITAA says that testing on arrival is having a negative impact on passenger confidence, as, if a test is returned as positive, they will have to quarantine at their destination.

In a statement this morning, ITAA CEO Pat Dawson said that departure testing would “restore consumer confidence in international travel.” 

He said: “First and foremost, the safety and comfort of our customers is paramount to all ITAA member travel agents. 

"We expect that there would be certain challenges involved in integrating these kinds of tests into the travel process; however, we believe that this method is worth implementing in order to restore consumer confidence in international travel. 

"It is essential that a global standard is developed and maintained for these tests so that all relevant parties can adhere to testing protocols.

"We believe that with the introduction of these testing measures, we will be able to restore a level of consumer confidence and begin to rebuild our industry," he added.

 

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