Non-contact infrared thermometers are commonly used in workplaces and restaurants as a screening tool for Covid-19, but a recent article by two leading experts have questioned the validity of these temperature checks. Dr William Wright at the Johns Hopkins University and Dr Philip Mackowiak, Emeritus professor of medicine at the University of Maryland, say the devices are inaccurate, unreliable and'lull people into a false sense of security'. MailOnline looked at seven thermometers available on the market to test their accuracy, and found that readings for a single healthy individual ranged from 36.2 C to 37.6 C. A reading greater than or equal to 100.4F (38 C) is considered a fever when taken outside of a healthcare environment. However, Dr Mackowiak told MailOnline the true reading for body temperature can only be obtained via a highly invasive procedure which inserts a thermometer into the pulmonary artery via a catheter. These are reserved solely for seriously ill hospital patients.
Leading doctors have warned against the use of infrared thermometers that scan a person's forehead to check for coronavirus infection. Such technology was widely deployed by shops, restaurants and workplaces as a form of screening to spot signs of fever, one of the main symptoms of Covid-19. But Dr William Wright at the Johns Hopkins University and Dr Philip Mackowiak, Emeritus, professor of medicine at the University of Maryland School of Medicine, have questioned their accuracy, and rubbished claims the devices are an effective tool in preventing the spread of Covid-19. In an editorial article published in Open Forum Infectious Diseases entitled'Why Temperature Screening for COVID-19 with Non-Contact Infrared Thermometers Doesn't Work', the world-leading experts assessed data on the technology. The equipment was widespread at the start of the pandemic, as little was known about the disease except it often manifested itself as a fever and a dry cough.
As lockdowns ease, thermal imaging cameras are popping up in all sorts of public places to assess the state of people's health. Using infrared technology, thermal cameras detect radiating heat from a body - usually from the forehead - and then estimate core body temperature. These cameras are an extremely powerful tool, often deployed by fire fighters to track smouldering embers and police to search for out-of-sight suspects. But they are not designed to be medical devices. So how useful are they in the current pandemic?
Anyone entering Martin Luther King Jr. Community Hospital in Los Angeles must pass before the electronic eye of the infrared camera installed last month. The worker monitoring its display sees color-coded boxes around each face in view: green if your skin temperature is less than 100 degrees Fahrenheit; red if it's 100 or above, which prompts a request to step aside for additional screening. "They don't have to stop, and if you get a green box you can keep moving," says Mark Reed, the hospital's director of support services. "It can do up to 16 people at a time." The hospital, which also requires employees and visitors to answer a daily questionnaire about their health, spent around $20,000 on the system after struggling to quickly screen staff with conventional thermometers during busy shift changes.
They can help reduce the risk of COVID-19 infections but shouldn't be the only safety measure employers take. Some employers are following White House guidelines to screen workers for a fever with daily temperature checks to help prevent the spread of infections. But screening for fevers alone won't eliminate risk. People with the virus can be contagious without a fever, so it's still important for employers to increase space between workers, disinfect surfaces and encourage hand washing. A person's temperature can be taken with a no-touch infrared thermometer pointed at the forehead, and workers can use the devices to take their own temperatures, using hand sanitizer before and after.