May 6, 2020

expert reaction to reports of Heathrow trialling temperature checks for passengers

It has been reported that Heathrow airport will start a trial of temperature checks of passengers.

Prof James Ferryman, Professor of Computational Vision at the University of Reading, said:

“Thermal cameras are very sensitive to the environment; they need to be calibrated well and then remain sensitive to, for example, distance from the person and ambient temperature. The calibration process needs to take account of the emissivity of human skin and the environmental temperature. The ambient temperature is unlikely to change very much within the confines of an airport, hence ought to perform within acceptable error bounds.

“Note, however, that not all people with COVID-19 present with a fever so this may limit to some extent the effectiveness of the approach. Many people with COVID-19 are asymptomatic.”

Prof Ashley Woodcock, Professor of Respiratory Medicine at the University of Manchester, said:

“Something like 3-5% of the population are asymptomatic and have normal temperature and are carrying COVID-19 in saliva and in the throat. So I don’t see how temperature screening helps control cross infection. We have to assume everyone is infectious and make sure our own protection is good enough.

“Live virus is not airborne in the community.  It can be spread in droplets from coughing, but, as far as I’m aware, no live virus has been detected in ordinary breath. 

“It is passed through physical contact with the virus on surfaces, so scrupulous hygiene, gloves and gel stations will get you through an airport and any public transport safely.  The risk is the Tube grab handles and the escalator handles.

“Extra attention and scrupulous hand hygiene are needed for food handlers.

“I accept that facemasks might be needed to build confidence (and passengers will wear them) but there is no evidence that they are effective in community situations.  They may be falsely reassuring.”

All our previous output on this subject can be seen at this weblink: www.sciencemediacentre.org/tag/covid-19

Declared interests

None received.