We’re three-quarters through 2020 and the world looks starkly different from the last. The most obvious changes are superficial: Masks on faces, restaurants spilled out onto sidewalks and parking lots, and handwashing stations line every entrance. All of these are well-evidenced ways to halt coronavirus. But a new method of coronavirus prevention is starting to become a mandatory norm in school districts across the country, including in New York City, the nation’s largest district, and in-state guidelines like California and Illinois: Temperature checks. The evidence backing them is less solid than masks and hand washing. So are temperature checks hygiene theater or an effective way to keep the sick out of public spaces and tamp down the spread of COVID-19?
There’s mounting evidence the former is the case and these temperature checks may just be a baseless trend.
For starters, they’re not going to catch anybody who’s pre-symptomatic or asymptomatic, says Logan Spector, a pediatric epidemiologist who refers to them as “infection theatre.” And they can indeed be quite theatrical. Take for example the company Related Companies, a developer behind the Hudson Yards complex in New York City, that installed fancy infrared cameras in building lobbies around the city that can signal when a person’s temperature is over 100 degrees. (The CDC defines fever as any temperature 100.4 F or greater).
So after a summer of the CDC requiring businesses to consider checking workers daily for symptoms like fever, it may come as a surprise that last week, the CDC announced that it’d stop requiring airport temperature screenings for international passengers from China, Iran, Brazil, and other countries because they fail to identify silent carriers.
“We now have a better understanding of COVID-19 transmission that indicates symptom-based screening has limited effectiveness because people with COVID-19 may have no symptoms or fever at the time of screening, or only mild symptoms,” the C.D.C. said in the statement. “Transmission of the virus may occur from passengers who have no symptoms or who have not yet developed symptoms of infection.”
This move comes after numerous published research studies that show that the science behind the effectiveness of temperature checks isn’t robust. Though fever is a common symptom of the coronavirus, there’s also strong evidence that suggests that coronavirus spreads before symptoms like a fever even appear. A study in June based at an Australian hospital shows that fever was detected in only 19 percent (16 out of 86) of the participants who had coronavirus. The researchers conclude that “using fever as a screening tool for COVID-19 may provide a false sense of security.” Instead, the authors suggest that “generic public health measures, such as self-isolation when sick, physical distancing and contact tracing, are more likely to be effective than widespread temperature screening.”
A more recent study based in South Korea from August highlights the issue of asymptomatic spread and offers more evidence that infected individuals who don’t necessarily feel feverish may carry the virus in their nose, throat, and lungs – in the same way as people with symptoms.
Temperature checks also cost big bucks. For example, a school district in Minnesota spent $20,000 on five digital temperature scanners to screen students, a big chunk of the $50,000 allocated to the school through the Coronavirus Aid, Relief, and Economic Security Act.
But before we entirely toss the idea of temperature checks out the window, there are a few benefits to them that need mention. The U.S. Food and Drug Administration highlights how non-contact temperature assessment allows a large number of people to be evaluated individually at points of entry. They also help reduce the risk of spread of COVID-19 infections from people who are symptomatic and have a fever. This may be especially worth noting in the context of schools, as the CDC lists fever as the most frequently reported coronavirus symptom in children. But there’s some evidence that suggests that as many as 45 percent of coronavirus infections in children are asymptomatic. The CDC also states that temperatures can be taken improperly and falsely interpreted as a fever.
So despite these benefits, they don’t serve many purposes for silent carriers, pre-symptomatic individuals, and instances where they’re administered incorrectly. In fact, some researchers have argued that temperature checks give us the illusion of safety and therefore, put us in further danger. If you walk into a store where you know everyone’s been screened, you could feel you’re in a safe place leading you to sanitize less than you normally would, or pull down your mask just below your nose.
For this reason, Spector strongly recommends that “whether or not people have been let in based on symptoms, you should keep your mask on indoors. And frankly, avoid congregating indoors as much as possible.”