zhu difeng - stock.adobe.com
Airlines and airports across the UK are turning to thermal surveillance cameras to reassure passengers they have measures in place to meet the challenges of Covid-19 as they prepare to resume passenger flights.
Airports including Heathrow, Manchester and London City claim that thermal scanners could help them identify passengers who may have the coronavirus by detecting people with an elevated temperature as they walk through the airport.
And a growing number of airlines and airports around the world are letting passengers know that if they are found to have a higher-than-normal temperature, they will not be allowed to fly.
All of this may be reassuring to people as the government opens up air corridors that will allow people to take overseas holidays, after three months of gruelling lockdown.
Yet the airports’ decision to trial and in some cases deploy thermal cameras as a solution to Covid-19 is not supported by science or UK government advice to the airline industry.
Multiple scientific studies have found thermal cameras are ineffective at preventing the spread of Covid-19 and other infections.
Thermal cameras may even be counter-productive, using up resources and expertise that might be better deployed preventing a second wave of the virus.
Security expert Bruce Schneier is a long-time critic of what he calls “security theatre”. He told Computer Weekly that there are two major problems with thermal surveillance sensors.
“Temperature is a bad proxy for having the disease and the measuring device is not very accurate,” he said.
The difference between a normal body temperature and a temperature caused by Covid-19 is just 1°C, leaving huge room for errors in temperature readings, particularly when cameras are used to scan multiple people in crowds.
Bruce Schneier, security expert
“You have so many false positives and false negatives,” said Schneier. “If the thing beeps, what are the chances you have Covid? Well, it could be a couple of things. You could have the fever for another reason. The thing is wildly inaccurate, so it could also be wrong.”
Health screening at airports has failed to detect most Covid-19 cases. A review by the US Communicable Disease Centre, for example, found 268,000 passenger checks at selected US airports led to the discovery of only 14 Covid-19 cases.
And a study by epidemioligists found that because of the incubation period of Covid-19, thermal scanners were “unlikely to prevent passage of infected travellers into new countries or regions where they may seed local transmission”.
According to the European Union Aviation Safety Agency (EASA), Between 1% and 20% of passengers with a fever will be missed by thermal screening equipment. And between 1% and 25% of passengers could be wrongly reported as having a temperature when they are clear.
Silkie Carlo, director at Big Brother Watch, who has been campaigning against the use of thermal imaging cameras to detect Covid-19, said airports were using unproven technology on passengers.
“It seems really that they’re just treating travellers like guinea pigs in a live experiment. And that’s going to be even more dangerous when they talk about the next stage, where they’re escalating passengers to health professionals,” she said.
Jenny Harries, deputy chief medical officer, told the government’s daily coronavirus briefing on 7 May 2020 that there was a case for thermal cameras as a “strong reassurance mechanism for the public”.
The likelihood of finding someone at the point they have a temperature – even with a reliable piece of kit – is “very small”.
“The other really important thing in relation to Covid-19 is that a sizeable proportion – up to about a third of people – do not have a temperature at presentation. They may have it variably through the illness, or they don’t have it,” she said.
The most recent UK government guidance for airlines and airports, on 22 June, also found there is no scientific support for the technology: “The current scientific evidence does not support temperature screening as an effective method to screen passengers for coronavirus.”
The government’s Scientific Advisory Group for Emergencies has advised that “there should be no requirement for temperature screening before passengers fly to enter, depart from, or fly within the UK”.
Similar warnings were issued by the World Health Organisation (WHO) and the European Aviation Safety Agency (EASA), which question the effectiveness of thermal screening at detecting and mitigating the Covid-19 pandemic.
Computer Weekly has identified over a dozen airports across the UK and Ireland that are either using or testing thermal surveillance cameras to try to control the spread of Covid-19.
The majority say they are conducting initial trials and have declined to say whether they will stop passengers who have a higher-than-normal temperature from flying when their monitoring systems become operational.
One exception is City Airport, which began thermal scans on its passengers this week.
London City Airport
While flights were suspended and the terminal was closed, London City Airport installed thermal scanning cameras, which were fully operational when flights resumed from the airport on Sunday 21 June.
The cameras are located at the entrance of terminals, at the arrivals corridor and at staff entrances. As with other airports such as Heathrow, Bournemouth and Manchester, there will be signage indicating their use to passengers.
Though other airports state they are conducting trials on the use of thermal cameras, Joe Rankin, head of communications at London City Airport, said its smaller, “more manageable setup” allows the airport to use cameras without a testing phase. “It’s not a trial … it’s operational and in place,” he said.
“The camera detects an elevated skin temperature and the computer alerts the operator to that passenger,” he said. “Our system is quite instantaneous, so it’s kind of like watching a live computer feed.”
Rankin said the cameras are a permanent fixture. The airport may put more effective alternatives in place at a later stage, such as health passports or “rapid testing” to allow passengers to show they don’t have the virus.
He said these additional measures would prove more useful than a thermal check, “which obviously isn’t testing anyone for Covid-19, just temperatures”.
Each passenger will be treated on a case-by-case basis, said Rankin. “If you walk down the corridor in the terminal and you have an elevated skin surface temperature on our system, that alone does not prevent you from flying,” he said.
Once a passenger is flagged as hot, they will be given the opportunity to pause and cool down. They may be asked to have their temperature taken again with a hand-held device, and asked to answer questions about their symptoms and health.
If the passenger has Covid-19 symptoms, the airport will inform the airline. “We will make a decision in conjunction with the airline, although ultimately, it’s for the airline to determine whether the passenger travels,” said Rankin.
This policy is not universal across airports. Cornwall Airport Newquay has stated the airport itself will not allow passengers to remain in the building or board an aircraft if they are found to have a temperature of 38°C or higher.
According to the airline KLM, a passenger will be turned away from a flight if found to have a fever, though family members will still be allowed to board.
Rankin said the temperature scanning equipment stores “data such as numbers of passengers” and “temperatures being recorded”.
The system is anonymised and does not store any personally identifiable information, he said.
“It doesn’t store an image of you that can be identified and used,” he said. “It’s not tethered to your booking with the airline or anything like that.”
Rankin said any data collected would be used by City Airport for analysing trends.
Heathrow presses for international standard for health screening
Heathrow Airport CEO John Holland-Kaye is pressing for the government and the aviation industry to develop a common international standard for health screening at airports.
The airport began trials of thermal cameras to detect passengers with raised temperatures at the Terminal 2 immigration hall and Terminal 5 on 21 May.
The cameras use facial recognition technology to identify people’s faces in order to take temperature readings of multiple people as they walk by.
Heathrow records the temperature readings, gender of passengers, their age group, whether they are a child, teenager, adult or alder, how fast a passenger is walking, whether they were wearing a face mask and other information about passengers which may affect their temperature, such as whether they were holding a cup of tea.
The airport claims, however, that this information will not be linked back to individual passengers or staff.
A spokesperson for Heathrow told Computer Weekly that it would not stop passengers or refer passengers with elevated temperatures to healthcare professionals during the trial.
Heathrow declined to say whether passengers with higher temperatures would be allowed to board their flights, if the system goes live.
“There isn’t an escalation process at this stage as we are just trialling the technology to understand whether it is medically beneficial, provides passenger reassurance and is compatible with an airport environment”.
Bournemouth plans to ‘intercept passengers’
Bournemouth Airport plans to introduce multiple thermal cameras in the departures and arrivals area that will allow “border staff to intercept any passengers showing signs of a high temperature.”
Dan Cartter, head of innovation at SCC, part of the Rigby group of companies which owns Bournemouth Airport, said that airlines are considering putting clauses in their terms and conditions that would allow people with a higher temperature to be refused access to a flight.
“Until the airlines state that, the airport is largely powerless to stop people getting on the flight,” he said.
During lockdown, some 200 engineers visited the airport daily to carry out maintenance work on grounded planes. The airport used a tripod-mounted thermal camera to monitor temperatures of staff as they passed through the security area.
Cartter said the cameras, which can automatically identify and focus on a person’s face, can identify temperature to an accuracy of plus or minus 0.5°C.
The trial did not identify any engineers with elevated temperatures, said Cartter, but it reassured airport staff that the airport was looking after their safety.
With passenger flights about to resume, the airport plans to install three thermal cameras to cover two entrance doors and the arrivals gateway in the airport – though no final decision has been taken.
Airport staff will give passengers who show signs of an elevated temperature government advice on Covid-19. That could include advising them to go home and isolate or to take further tests, said Cartter.
“You need to find people at the entrance before they have interacted with other people and infected other people,” he said.
Airlines likely to be given the final say
Some European airports, including Brussels and Venezia airports, explicitly state on their websites that passengers detected with temperatures above normal will not be allowed in the terminal.
It is likely that airports will follow London City by delegating the decision to bar or accept passengers who appear to have a higher-than-normal temperature to airlines.
Unlike airports, airlines can change their terms and conditions to exclude people who do not pass temperature checks.
Many are already taking passengers’ temperatures before they board. Ryanair, easyJet and Air France, for example, warn on their websites that people who fail temperature checks may denied travel and sent home.
What airlines say
Air Canada: The airline introduced a temperature check policy on 15 May and requires passengers to undergo a touchless temperature screening during airport check-in. It says that when customers are found to have an elevated temperature (37.6°C and above), it will consult with its medical experts before making a final decision about eligibility to travel. Customers who are deemed unwell to travel will be rebooked at no cost, but will be required to obtain medical clearance prior to travel.
Air France: Air France began the gradual introduction of passengers’ body temperature checks with contactless thermometer from 11 May. Passengers are warned: “Your temperature must be below 38°C. If your temperature is higher than this, you may be denied boarding.”
British Airways: International Consolidated Airlines Group, owner of British Airways, Aer Lingus and Spanish airline Iberia IAG, has told investors that it it backs passenger temperature checks at airports if it helps some services resume after an easing of Covid-19 restrictions.
easyJet: The airline warns customers that there may be pre-flight temperature checks at some airports. Those who do not pass the test will be unable to travel.
Ryanair: Ryanair warns passengers they may have their temperature checked at the airport and could be asked to go home.
Yet science makes it clear that thermal screening for temperatures is not effective at diagnosing infections. Airports have used them in the past to try to control other infections – with less than impressive results.
Scientists in New Zealand, for example, found that thermal cameras were “not much better than chance” at identifying passengers who were likely to be infected with influenza.
Their chief benefit would be “to deter unwell people from travelling, or to demonstrate to their citizens that they are doing everything they can to protect population health”.
“Easily visible measures, such as thermal scanning machines, may generate a sense of confidence or reassurance that disease will be detected and prevented from entering the country,” they said.
But any sense of reassurance could be quickly dispelled when it becomes clear that cameras are failing to prevent the spread of the disease.
Profiling is ‘deeply concerning’
There are questions, too, about whether using cameras to perform mass checks on passengers is proportionate under data protection and human rights laws.
The UK’s Surveillance Camera Commissioner wrote in April that in the unique time of a pandemic, it might be proportionate to use thermal scanning as a condition of entry, if people have given consent.
But he said: “Mass use without individuals’ knowledge seems disproportionate and would require much stronger justification.”
Big Brother Watch’s Carlo said Heathrow Airport had fallen short of this requirement by failing to give passengers an obvious option to opt out of walking by the cameras.
Heathrow Airport’s website says passengers who want to avoid the cameras can talk to airport staff and ask to use a different route, but that information is hard to find, said Carlo.
She has also queried Heathrow’s plans to store anonymised data about passengers. The fact the information is recorded anonymously or, in the case of Bournemouth, isn’t recorded at all, does not make such monitoring legal, she said.
“The fact is that it is yet another kind of checkpoint, and this time a health surveillance one. We are getting more towards the monitoring of our bodies and our health. It’s about the loss of rights that will happen there and then,” she said.
EASA – thermal scanning ‘ineffective’
The European Union Aviation Safety Agency and the European Centre for Disease Prevention and Control are advising airports and airlines how to re-open as lockdown measures are eased.
Their guidance document concludes that thermal screening of passengers has many limitations and that there is little evidence of its effectiveness in detecting Covid-19 cases.
The International Air Transport Association (IATA), a trade group which represents 290 airlines, told Computer Weekly it gives guarded support for temperature as part of a “multi-layered approach” to restarting aviation.
And IATA is clear about the limitations: thermal scanning measures the surface temperature of travellers, which is less reliable for detecting illness than measuring their core temperature.
Thermal scanning will not detect people with early-stage illness, asymptotic illness, those with symptoms that do not include fever, or those who have taken medicines such as paracetamol to reduce their temperature, it said.
Across Europe, airports including Paris, Brussels and Venice, and now the UK, are buying into thermal screening.
One exception is Germany, where Munich Airport told Computer Weekly that German health authorities have concluded that thermal screening of passengers adds negligible value to the health screening measures already in place. A spokesperson said: “General fever measurement for all arriving passengers would be ineffective.”
EASA warns that effective screening of passengers entails huge human laboratory and logistical resources, which will detract from the preparedness planning for a potential second wave of the Covid-19 pandemic.
Christian Ionut Panait, a medical expert for the Romanian Civil Aeronautical Authority and director of communications for EASA, said thermal screening alone should never be used as the basis for preventing someone travelling.
“As fever can have a variety of reasons, a person being identified with fever should undergo a comprehensive assessment performed by a healthcare professional to try to isolate the cause of the fever. Based on this assessment, the health authorities should decide whether the passenger may board the flight or not,” he said.
So why do it? There are three reasons, said Panait. Thermal screening might identify a passenger who did not know they had Covid-19 symptoms. Second, the technology has a deterrent effect for infected passengers who might be tempted to fly.
“And last,” he said, “it has a reassuring effect for passengers, crew members and staff that all possible measures have been taken in order for them to have a safe journey or work experience, as applicable.”
The science shows thermal surveillance is far more about making passengers feel safe than it is about controlling the risks of Covid-19.
In the words of IATA, surveys during the Covid-19 outbreak have “indicated that airline passengers are reassured by temperature screening” at airports and it could also “deter passengers who might otherwise travel while feeling unwell”.
The risk of such safety theatre is that it will divert resources and attention away from planning for and mitigating a second wave of the virus.
Temperature surveillance plans at UK and Irish airports
Belfast International Airport: Belfast is not testing temperatures of passengers. It notes that “the latest government advice is that temperature screening is not effective on its own”.
Bournemouth Airport: Bournemouth is testing a thermal temperature testing camera supplied by SCC in the staff entrance. It plans to introduce additional thermal cameras across the terminal building to enable border staff to “intercept any passengers sowing signs of a high temperature”.
Birmingham Airport: Birmingham Airport is trialling thermal imaging and expects to roll it out for departure passengers from 1 July 2020.
City of Derry: City of Derry introduced thermal scanning equipment supplied by Hikvision on 12 June 2020. Every person who goes through the terminal will be scanned. People with a temperature of 38°C or above will be asked to step aside for a secondary cross-check using a hand-held contactless thermometer. Any person with a temperature reading of 38°C or above will be advised to seek medical advice before onward travel.
Edinburgh Airport: The airport is trialling “temperature checking technology” for departing passengers. Passengers will be asked to have their temperature taken but can decline. It warns: “Some airlines are also asking that passengers have their temperatures checked before boarding.”
Liverpool John Lennon Airport: Liverpool’s airport has temperature screening devices but has not deployed them. A spokesperson told Computer Weekly: “We aren’t using them so far, in line with the government guidance which states that the current scientific evidence does not support temperature screening as an effective method to screen passengers for coronavirus. The advice is that there should be no requirement for temperature screening before passengers fly to, enter, depart from, or fly within the UK.”
London Gatwick: The airport has conducted a temperature checking trial. It said that following Public Health England (PHE) advice, there are currently no permanent temperature checks at Gatwick or any other UK airport. According to PHE’s medical, clinically informed and evidence-driven approach to identify those at risk, temperature checks are not a required or effective way of keeping the public safe.
London Heathrow: Heathrow is conducting trials of thermal cameras in the Terminal 2 immigration hall and the Terminal 5 departure halls, capable of screening multiple people simultaneously. The airport says that during the trial it will not process, capture, store or share any personally identifiable information of passengers. It plans to roll out the technology in other parts of the airport if the initial trials are successful. In subsequent phases, passengers with a temperature may be referred to healthcare professionals. It warns passengers that “some airlines may conduct their own temperature checks at check-in or gate rooms”.
London Southend Airport: Southend Airport has installed thermal cameras to screen passengers since early June in preparation for the airport re-opening in July. It told Computer Weekly: “Once flights resume, we will monitor temperatures and review the data collected.”
London Stansted: The airport is conducting limited temperature screening. It said: “Initially, during this trial phase, this will be to test equipment, and results will not be communicated to passengers or used to decide whether a passenger can travel.”
Manchester Airport: Manchester Airport is using a thermal camera in Terminal 1 security to scan the temperatures of passengers. The technology is a trial and passengers will not be told the results of the scan. It will not affect their ability to travel. A spokesman for the airport said the trial was testing equipment and that the equipment was clearly signposted to passengers. A spokesman said, “while the equipment is in testing phase, passengers are not being denied travel as a result of any testing”, but declined to give further details.
Newquay, Cornwall: Newquay has installed thermal imaging cameras in the terminal. Airport staff will escort someone with a of 38°C or higher to a separate area within the terminal, where they will be able to wait and later come back for a second test. Passengers who fail the second test will not be allowed to remain in the airport or to board a flight.
Newcastle International Airport: Newcastle has bought and plans to test “temperature testing technology”. Passengers using AirFrance will be subject to systematic checks with infrared thermometers. AirFrance Passengers are warned: “Customers whose temperature is higher than 38°C may be denied boarding and their reservation will be changed at no extra charge to a flight at a later date.”
Norwich Airport: Norwich, which is owned by the Rigby Group, plans to introduce trials of thermal cameras according to local press reports, following trials at Bournemouth, another airport in the group.
Temperature surveillance plans at European airports
Brussels Airport: Brussels Airport is installing thermal cameras to identify persons with elevated body temperature but also to detect passengers who fail to wear a face mask. The cameras will be placed in front of the departure hall to check all passengers before they enter the terminal. “Persons with a body temperature of more than 38°C can be denied access to the terminal.”
Minsk International Airport: Minsk is using thermal scanners in arrivals to measure passengers temperatures.
Munich Airport: Munich, in common with other German airports, has ruled out taking temperature readings of passengers. It says that temperature screening of passengers is regarded as ineffective and adds negligible value to other infection control measures.
Paris Airport: Paris Aéroport is setting up thermal cameras in the luggage delivery area for people on arriving flights. Passengers with temperatures over 38°C will be invited to have a second temperature check with a contactless thermometer. The airport will suggest that passengers with a confirmed high temperature consult with a doctor, who can offer a Covid-19 PCR test. Some airlines are checking passengers’ body temperature before they board. The airport warned passengers: “As of 11 May, Air France is gradually implementing passenger body temperature checks with contactless thermometer. Your temperature must be below 38°C. If your temperature is higher than this, you may be denied boarding.”
Rome Fiumicino Airport: The airport is using thermal scanners to check departing passengers before they enter the terminal. Thermal scanners have been in use since 4 February.
Spain: AENA which manages is holding talks with the Spanish Ministry of Health about introducing health checks at 46 airports it manages in Spain. AENA says it supports the installation and use of thermographic cameras and the development of a “passenger location register” which will be managed by the Ministry of Health.
Venezia Airport, Venice: The airport has installed thermal cameras in the arrivals and departures areas of the terminal to check body temperature and to “report anomalies”. The airport warns passengers flying out of Venice: “Your body temperature will be checked through a thermal camera (thermoscanner); if it exceeds 37.5°C, you won’t be allowed to access the terminal and will go through an additional check by medical staff.”
Vienna International Airport: All travellers arriving at Vienna Airport are subject to body temperature measurements.
What the scientists say
In a February 2020 advisory note on Covid-19, the World Health Organisation (WHO) warned that “temperature screening alone may not be very effective as it may miss travellers incubating the disease or travellers concealing fever during travel, or it may yield false positive (fever of a different cause)”. It said that if temperature screening is implemented, it should be accompanied by health questionnaires, which should be promptly evaluated. Notices informing passengers what symptoms to look out for and where to seek medical support should be made available.
Epidemiologists from the Center for the Mathematical Modelling of Infectious diseases nCoV working group found that thermal scanning at airports was of limited value for preventing the spread of Covid-19. A February 2020 study found that “due to the duration of the incubation period of 2019-nCoV infection, we find that exit or entry screening at airports for initial symptoms, via thermal scanners or similar, is unlikely to prevent passage of infected travellers into new countries or regions where they may seed local transmission”.
The European Centre for Disease Prevention and Control said in a technical report for public health authorities in May 2020 that thermal screening of passengers is a “high-cost, low-efficiency measure”. Evidence from the early phases of the Covid-19 pandemic indicates that entry screening is “ineffective in preventing SARS-CoV-2 virus introductions”. It said that while entry screening processes may help dissuade ill persons from travelling and enhance public confidence, communication needs to be carefully balanced in this case, to avoid creating a false impression of security.
The European Union Aviation Safety Agency (EASA) and the European Centre for Disease Prevention and Control advised airlines and airports on 21 May that “it should be recognised that thermal screening has many limitations and little evidence of effectiveness in detecting Covid-19 cases”. Many symptomatic people do not have a fever and a large percentage of Covid-19 infections are transmitted by people without symptoms. Thermal screening “may give a false impression of safety”, it said, and its implementation “requires public health resources that could be better invested in other measures”.
The European Centre for Disease and Control reported on 26 May that, based on current knowledge, relatively large numbers of people with Covid-19 will be in the incubation phase without symptoms while travelling. Covid-19 has an incubation period of 2-14 days, with 75% of cases developing symptoms in a period of between four and seven days. “These travellers,” it said, “will not be detected by exit or entry screening, even in a scenario assuming high-sensitivity detection of symptomatic travellers.”
A study by scientists in New Zealand in 2011 found that infrared thermal imaging scanners were not effective for mass screening passengers arriving at airports for influenza. The scanners performed “moderately well” in detecting fevers. But the cameras were “not much better than chance” at identifying passengers that were likely to be infected by influenza. The authors said governments could introduce screening for other reasons than to detect influenza, for example “to deter unwell people from travelling, or to demonstrate to their citizens that they are doing everything they can to protect population health”. But this would risk the potential loss of public confidence during a flu pandemic when it becomes clear that many infected travellers were not detected by screening when they entered the country.
In 2005, a study by Canadian scientists found that health screening passengers arriving at Canadian airports failed to detect a single incidence of Sars. The study found that because Sars had a low prevalence, the positive predictive value of screening was “essentially zero”. The scientists said that “easily visible measures, such as thermal scanning machines, may generate a sense of confidence or reassurance that disease will be detected and prevented from entering the country”. But any sense of reassurance could be quickly dispelled when the first case was detected despite screening measures.
The International Air Transport Association (IATA)’s medical advisory group published a paper on 27 April on “restarting aviation following Covid-19”. It found that temperature screening would miss many of those with early-stage illness, those who are infected but have no symptoms, or have taken medication such as paracetamol to lower their temperature. It found that research during Covid-19 “indicted that airline passengers are reassured by temperatures screening undertaken in airports”. Temperature screening needs to be done with validated equipment or manually by trained staff, but it warns that even then there will be false positives and false negatives. Screening is more likely to be useful where Covid-19 prevalence is higher, such as “returned travellers” rather than the general travel population. “It may be of some benefit, applied selectively along with other measures.”