UNC Medical Center’s David Weber, MD, MPH, co-authored a review study with Massachusetts General Hospital’s Erica Shenoy, MD, PhD, on routine screening of healthcare workers, showing it does not prevent hospital transmission.
Routine testing of asymptomatic healthcare personnel (HCP) in the absence of confirmed exposures to COVID-19 is not a recommended strategy for preventing transmission of SARS-CoV-2 causing the current global pandemic, according to a new review co-authored by David Weber, MD, MPH, professor of medicine at the UNC School of Medicine and Medical Director of Infection Prevention at the UNC Medical Center, and Erica S. Shenoy, MD, PhD, associate chief of the Infection Control Unit at Massachusetts General Hospital (MGH). The review, published in Infection Control & Hospital Epidemiology, found that such testing is unlikely to affect the transmission of SARS-CoV-2 in healthcare settings and could even have unintended negative consequences.
Many universities, sports leagues and other institutions require individuals in their organization to undergo routine testing for COVID-19, whether or not they are experiencing symptoms. Current public health recommendations are to test individuals with symptoms consistent with COVID-19 and those with confirmed exposures. At some health systems, asymptomatic employees are provided access to testing when it is required (such as for travel), but routine surveillance of healthcare personnel has not been pursued.
“People were constantly asking: If sports teams and local universities are doing routine asymptomatic surveillance, why aren’t we doing this in healthcare? Wouldn’t it make care for our patients safer?” said Shenoy.
Shenoy learned that her colleague at other hospitals were being asked the same question, so she and Weber performed a focused review of healthcare-associated transmission as well as what is known about the frequency of infection among asymptomatic healthcare providers, addressing the common questions they had received:
– What portion of asymptomatic healthcare personnel have undiagnosed COVID-19 infections?
– Do asymptomatic healthcare personnel with undiagnosed COVID-19 pose an infection risk to patients?
– Do patients with undiagnosed COVID-19 pose an infection risk to healthcare personnel?
Shenoy and Weber compiled data from MGH’s voluntary testing program as well as several other hospitals that had either screened or made COVID-19 testing available to asymptomatic healthcare personnel. Infection rates ranged from 0.2% to 0.4% (i.e., 1 in 250 to 1 in 500).
“That’s quite low,” said Shenoy. MGH’s asymptomatic on-demand testing program continues, and the frequency of positive COVID-19 tests in healthcare personnel prevalence has remained below 1%. “This low prevalence means that in a routine surveillance approach, you would have to test a lot of people in order to detect one asymptomatic case.”
Given the low frequency of positive tests, the possibility of false positive results is a concern, and Shenoy and Weber describe how facilities considering routine surveillance must consider whether confirmatory testing would be used to address the possibility of false-positive results.
“This is the most comprehensive paper to review publicly available results for routine COVID-19 testing of asymptomatic healthcare providers,” said Weber.
Meanwhile, a negative test result should have no impact on a HCP’s day-to-day actions, said Shenoy, who is also an assistant professor of Medicine at Harvard Medical School.
“Being negative today doesn’t change anything that we do in the hospital,” she says. “If I test negative today, I’m still wearing my surgical mask at work and my cloth mask when outside of work. I’m still physically distancing and doing my symptom monitoring.”
Yet it’s possible, she added, that healthcare providers who test negative may change their behavior and relax their guard outside of the clinical setting, such as not wearing a face covering in the hospital break rooms or choosing to attend gatherings outside of work.
The literature suggests that the risk of healthcare personnel and patients transmitting the coronavirus to one another is very low when effective safety protocols such as wearing masks, testing when indicated, and screening symptomatic patients are followed. Reported instances of healthcare personnel acquiring infection through exposures to patients show overall low risk of transmission. Similarly, risk to patients from asymptomatic infected healthcare providers has also been reported to be low, highlighting the efficacy of current protocols, Shenoy and Weber found.
Instead of considering routine screening of healthcare personnel for COVID-19, hospitals should continue to focus on interventions that are known to reduce spread of the disease, which also include rapid identification and isolation of patients who are suspected of COVID-19, proper use of personal protective equipment when appropriate, and testing asymptomatic patients known to have been exposed to the coronavirus.
“Healthcare is not a bubble,” said Shenoy, “and routine surveillance won’t make it one.”
Media contacts: Noah Brown, Boston Mass General; Mark Derewicz, UNC Health