Scientific evidence to support the practice of temperature screening for facility entry is limited, mostly based on airport entry screening, and goes back to screening during SARS 2003, H1N1 2009 and Ebola. In one study, over 12 million people were screened in and around Beijing in 2003 using infrared thermometers
and only 12 probable cases of SARS were detected.1
Similarly, entry screening to Australia, Canada and Singapore did not detect any SARS cases.2
Between August 2014 and January 2016, this review found, not a single Ebola case was detected among 300,000 passengers screened before boarding flights in Guinea, Liberia, and Sierra Leone, which all had large Ebola epidemics. However, four infected passengers were not stopped by exit screening as they did not have symptoms. There is less data for ground and port crossings and even less for facility entry. After the SARS epidemic of 2003, an Australian Perspective article in Emerging Infectious Diseases concluded border screening was not recommended and advised effective communication with travelers and clinicians instead.3
Nonetheless, anecdotal cases, the hope that it will prevent individuals who are ill from entering the building, either through identification of those with a fever or as a deterrent and an urge to do something, has led many employers to implement or jurisdictions to recommend or require temperature screening. Temperature screening
has become a common component of the mitigation efforts in the fight against COVID-19. While some will have employees check their temperature prior to coming to the workplace, some require the employee to report while others ask the employee to show their thermometer (and yes, there’s even an app for that), some will do on-site temperature checks. Entry temperature screening can also be used as part of a more comprehensive symptom screen and opportunity to educate employees of other important steps to prevent the spread of the infection such as social distancing, hand washing and use of face covering.
With SARS CoV-2, there are the added realities of asymptomatic and pre-symptomatic spread before a fever develops, the fact that a large proportion of COVID 19 patients present without fever, or may use antipyretic medications. Added to this are the issues of sensitivity and specificity, in a population with low disease prevalence will have a low predictive value, both positive and negative. In addition are problems of the temperature screening device accuracy, calibration, agreement on the cutoff, ambient temperature effect on the screening. Screener concerns
include training, appropriate use of PPE and hazards to the person taking the temperature even with touchless devices. Some camera systems have been developed which may avoid this last concern for the screener but these may not be practical or validated in facility use. FDA has issued guidance on these devices. A recent review of the published manufacturer specifications for Accuracy of a body temperature scanner (Seek Scan) able to be performed at 5 feet was +/- 0.5 degrees F (+/- 0.2 degrees C), compared to a temporal scanner (Expergen) reported as +/- 0.2 degrees F (+/-0.1 degrees C).
Paid sick leave is recommended to reduce the chances that a worker will come to work with COVID-19. Temperature screening of workers without paid leave may seem to be of greater value, but this is unproven.
Given the limitations of on-site entry temperature screens, the Centers for Disease Control and Prevention (CDC) still notes that screening employees for COVID-19 symptoms (such as temperature checks is an optional strategy that employers may use. If employers choose to do so, they should offer guidance on appropriate steps to take.6 The World Health Organization (WHO) notes that temperature screening alone, at exit or entry, is not an effective way to stop international spread”.7
The EEOC noted that an ADA-covered employer may take its employees’ temperatures to determine whether they have a fever. It would be considered a medical examination and “as with all medical information, the fact that an employee had a fever or other symptoms would be subject to ADA confidentiality requirements.”7
Record keeping may vary depending on state requirements but with respect to OSHA, If the employer documents the temperature screening it must be maintained consistent with 29 CFR 1910.1020, for the duration of employment plus 30 years.
Despite the limitations of temperature screening, it is mandated by many cities, counties, and states. Some jurisdictions require screening of all workers, while others may only require screening once there has been a case of COVID-19 in the workplace.
In summary, temperature screening has not been shown to significantly impact the spread of COVID-19 based on current science. If it is used it should be part of a larger education and pre-work screening effort which could include symptom screening and reminders of the importance of social distancing, good hand hygiene, and face coverings. There should be careful attention to follow up steps for those who are instructed not to proceed to work and well as attention to all the concerns described above including
: how to keep information confidential; how to take temperature and maintain physical distance; how to proceed if an employee refuses to have their temperature taken and the return to work procedures if an employee does have an elevated temperature.