• Sebastian Leck

FACT CHECK: Are temperature checks at airports an effective way to prevent the spread of COVID-19?

Updated: Jul 2, 2020

FALSE. Temperature screenings alone are not effective at preventing the COVID-19 virus from spreading, but they can be helpful if they are used along with other measures. The Canadian government will be combining temperature screenings with a list of health questions and mandatory face masks in the hopes of containing the spread of the virus.

On June 12, the federal government announced that it would be mandating temperature screenings for any travellers arriving to Canada or leaving from Canadian airports. Passengers who have fevers will not be allowed to board their flights, and airport employees will also be tested for fevers. By the end of July, the government plans to install temperature-screening stations in Montreal, Toronto, Calgary, and Vancouver airports.

However, it’s not clear that it will make a difference. Over the past few months, public health experts around the world have said temperature screenings won’t prevent outbreaks. Even Canada’s chief public health officer, Theresa Tam, has said that temperature-taking is “not effective at all.” As travel to Europe becomes possible again, it will be important to know if these screenings actually work or if they’re largely for show.

Temperature checks detect only fevers, not infections

If a test checks only for body temperature, it is likely to miss many people infected with COVID-19. A study of 5,700 patients at a New York City hospital found that only 30.7 percent of those who tested positive showed symptoms of a fever when they first arrived. Since it can take between one and fourteen days to begin showing symptoms, patients who don’t have fevers when they are tested may develop them later.

Temperature scanners can also produce false positives and false negatives, and fever-suppressing drugs could mask symptoms in travellers.

In a paper that appeared in Eurosurveillance this February, researchers predicted that temperature screening would miss 46 percent of positive cases. Between February 2 and 23, the US government screened around 46,000 air travellers who had been in China and detected only one positive case. In March, eight passengers who passed through temperature screening at the Shanghai airport all later tested positive for COVID-19.

Temperature screenings haven’t been helpful for detecting diseases that came before COVID-19 either. A paper in the International Journal of Environmental Research and Public Health found that exit-screening measures for Ebola and SARS—which included temperature screenings and a health questionnaire—didn’t catch any positive cases in the countries the researchers studied. In 2003, Canadian airport authorities scanned more than 750,000 people for SARS but detected no positive cases at all.

Temperature checks should be used as one tool among many

Despite the disappointing results, exit screenings could still be useful. The team of researchers who studied the spread of Ebola wrote that, because exit screenings are so visible, they can discourage people who might be sick from travelling. They recommended that governments continue to use exit screenings but only alongside other measures, such as contact-tracing, vaccination, and quarantines.

The World Health Organization gives similar advice. It says temperature screenings alone “may not be very effective” but suggests using them alongside other tools, like providing travellers with health information and having them fill out a questionnaire that includes information for contact-tracing.

Canada’s airport screening measures will include health screening questions, temperature screenings, and mandatory face masks. Prime Minister Justin Trudeau has said the screenings are “not a way of detecting COVID-19 in travellers” but that they can detect symptoms of the virus and “highlight if someone is ill and shouldn’t be travelling at all.”

Overall, temperature screenings alone are not effective at detecting positive cases of COVID-19. However, they can help catch some cases of COVID-19, discourage travel, and educate people about the virus and its symptoms.