As Canada continues to reopen, some grocery stores, salons and other businesses have implemented temperature screening — an approach that uses a touchless scanner to measure a person’s body temperature — in an attempt to prevent the spread of the novel coronavirus.
The process was made mandatory for all air travellers in Canada in mid-June. Any passenger who shows a fever on two measurements, taken 10 minutes apart, will be asked to rebook after 14 days.
However, some experts wonder whether the step is effective given a person can shed the COVID-19 virus without having a fever or any change in body temperature. The tool often used to measure temperature has also been shown to be unreliable.
READ MORE: Temperature screening not always reliable to mitigate coronavirus risk, experts say
For those reasons, temperature screening has not been recommended by Canada’s chief public health officer Theresa Tam. In fact, she quickly shut down the approach when more businesses began implementing the practice in May.
“The more you actually understand this virus, the more you begin to know that temperature-taking is not effective at all,” Tam said in a ministerial update that month.
Tam said the likelihood of screening someone who was symptomatic was “relatively inefficient” in comparison to those who were asymptomatic.
“If we have a significant number of asymptomatic or pre-symptomatic people, that also even reduces the effectiveness even more.”
Dr. Susy Hota, the medical director of the Infection Prevention and Control and Medical Device Reprocessing department at the University Health Network in Toronto, agrees.
“There really are a lot of limitations to temperature checks, and I’m not really convinced that they’re worth investing in for this purpose,” Hota said.
READ MORE: Canada to screen air travellers for fever amid coronavirus pandemic: Trudeau
There are also inaccuracies with the temperature probes used for this purpose, Hota said.
She worries they can give patrons and business owners a “false sense of security.”
Is temperature screening an effective way to detect COVID-19?
Temperature screening is typically not an effective way to detect COVID-19 when used on its own, and that’s because of the way the virus spreads.
“When we talk about the issue of pre-symptomatic shedding and transmission, we’re talking about people who have no symptoms yet — so no fever,” Hota said.
“Once you’ve developed the fever, we know what we’re dealing with … but in the pre-symptomatic phase, a temperature check won’t help.”
Problems can also arise from the touch-less temperature probes currently being used in airports, grocery stores and by other businesses.
“It’s a variable that … isn’t infallible,” said Dr. Leighanne Parkes, infectious disease specialist and microbiologist at the Jewish General Hospital in Montreal.
“It depends on the instrument that we’re using, the ambient temperature, (if) the instrument is calibrated correctly, is the individual coming in from a hot outside or a cold outside?”
All these things come into play when a temperature probe is used, making true measures hard to come by.
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There are also other reasons a person’s body temperature could be elevated that don’t have to do with COVID-19.
Medication, certain pre-existing conditions, weather and what you were doing immediately prior to having your temperature checked are all factors that can affect your body temperature, Hota said.
“It is possible that your ambient temperature and what you were doing before … might register a higher temperature than you really would have otherwise,” she said.
However, Parkes believes temperature screening could be helpful when it’s “bundled” with other preventative health measures.
Temperature screening should be considered just one layer in a “pyramid of prevention,” she said.
“It’s not a replacement for the other means that we have in place, such as social distancing, masking in public spaces, adequate ventilation, adequate environmental cleaning … all those things combined.”
Can a business refuse to serve me if my temperature is considered ‘too high?’
Although temperature screening may not accurately detect COVID-19, it’s still within the rights of a business to deny you service on the grounds of a high temperature.
This is because employers and employees have the right to a safe working environment.
“You can’t be denied entry on grounds of race or religion … because that’s discrimination, but if your temperature is above some arbitrary scale, then you can be denied entry,” said Bernard Dickens, professor emeritus of health law and policy in the faculty of law, faculty of medicine and Joint Centre for Bioethics at the University of Toronto.
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“It’s a security ground … to protect the staff who work in the facility. They have a right to a safe working environment, and the store is responsible for the safety of its employees.”
For this reason, you can refuse to take a temperature test, but the store can refuse your entry upon doing so.
Questions about COVID-19? Here are some things you need to know:
Symptoms can include fever, cough and difficulty breathing — very similar to a cold or flu. Some people can develop a more severe illness. People most at risk of this include older adults and people with severe chronic medical conditions like heart, lung or kidney disease. If you develop symptoms, contact public health authorities.
To prevent the virus from spreading, experts recommend frequent handwashing and coughing into your sleeve. They also recommend minimizing contact with others, staying home as much as possible and maintaining a distance of two metres from other people if you go out.
In situations where you can’t keep a safe distance from others, public health officials recommend the use of a non-medical face mask or covering to prevent spreading the respiratory droplets that can carry the virus.
For full COVID-19 coverage from Global News, click here.
— With files from Global News’ Emerald Bensadoun