The answer, according to experts, is no.
Temperature controls are an important tool that can be effective in many contexts, including doctor’s offices and hospitals. But when it comes to curbing the global spread of coronavirus that causes covid-19, temperature screening has serious limitations – and it involves costs.
What can be lost
The biggest problem is that temperature screening can lose cases by inadvertently sending sick people. It can also provide false positives, potentially sending healthy people to spaces where others are seriously ill.
It is difficult and expensive for some jurisdictions to purchase sufficient screening equipment and train staff to use it. For this reason, some governments choose to focus on other measures, especially if resources are scarce.
“A thermometer, if properly calibrated and used, can detect fever. Great. We are all happy about it, ”said Isaac Bogoch, an infectious disease specialist at Toronto General Hospital. “But is it an effective method for screening people for covid-19 infection? The answer is no.”
The use of temperature screening in response to this coronavirus has so far been inaccurate, with some countries taking over and others moving away.
China, for example, has made extensive use of temperature screening by setting up checkpoints not only in airports, but outside condominiums, including in stores. India is testing all international arrivals at airports. South Korea, Russia and others are checking for arrivals from certain places.
Many variables on the readings
Other countries don’t care. Even with an outbreak in Italy, German health officials have argued that airport temperature controls are not effective.
There are several reasons why temperature screening is not effective on its own.
To start, in crisis situations, people can use inappropriate tools or use the right tools incorrectly, leading to inaccuracies.
“We are seeing photographs of people using industrial grade infrared thermometers to measure people’s temperature, but these tools are not meant to measure the temperature of the human body,” said Jim Seffrin, infrared device expert at the Infraspection Institute in New Jersey.
Seffrin said that industrial grade instruments are calibrated to measure things like pipes. Using them to measure the temperature of human skin can lead to dull numbers of up to 7 degrees Fahrenheit, he said.
It also matters where and how you use them. People have used infrared thermometers on people standing outside in the winter cold. Since this type of instrument measures surface temperature, not body temperature, this could mean losing a fever.
False positives are also possible. “A person may present themselves with an above-average surface temperature because he has just gone out for a jog, or may have been standing near a warm-up lap, causing them to become hot,” said Seffrin.
Another problem: people taking medicines to mask fever.
Even if performed correctly, temperature checks are not necessarily sufficient to identify the right cases.
Yanzhong Huang, a senior member for global health at the Council on Foreign Relations, said temperature checks could catch someone with the flu fever, but they might miss someone who was infected with covid-19 but not it is still showing symptoms.
“Screening may be partially effective, but it will not be effective for asymptomatic carriers,” he said.
Huang pointed to research that during the H1N1 epidemic, border screening identified only about a third of cases.
More recent studies also question the effectiveness of airport-type screening.
Researchers from the European Center for Disease Prevention and Control found that three-quarters of passengers leaving covid-19 with Chinese cities would not be detected by the entrance screening.
Entry and exit screening “is unlikely to prevent the passage of infected travelers to new countries or regions where they can sow local transmission,” found a study by a team from the London School of Hygiene & Tropical Medicine.
World Health Organization guidelines suggest that thermometers may be part of a broader strategy, including interviews and data collection on recent travel and contacts.
For countries with resources and equipment, temperature controls can also be a starting point for educating the general public about what is happening, how to stay safe and what to do if they get sick.
Part of what the screening does is signaling that, yes, the authorities are doing something – and that’s important, experts said.
“If the community thinks you’re doing nothing, it won’t buy your other public health policies like the social removal measures everyone should employ on a large scale right now,” said Bogoch, the infectious disease specialist.
“Optics are really important.”
Min Joo Kim in Seoul, Joanna Slater in New Delhi and Loveday Morris in Berlin contributed to this report.