BIRMINGHAM, Ala — In the late spring and early summer of 2020, while the number of positive cases of COVID-19 was increasing in the United States, this baseline study shows infection rates among health care workers in large hospital emergency departments remained low, despite reports of high infection rates at the initial epicenters of the pandemic. Additionally, a significant number of those workers who were infected with SARS-CoV-2 were unaware of their exposure to the virus.
The Centers for Disease Control and Prevention sponsored a large, multi-center project at 20 high-volume emergency departments in the nation. The Department of Emergency Medicine at the University of Alabama at Birmingham participated in the study.
Overall, only 2.8 percent of emergency department staff in the 20 sites had diagnosed COVID-19 infection during initial assessment, a total of 193 persons out of 6,788 enrolled nationwide. Subsequent testing of 1,606 health care workers not known to have COVID-19 found an additional 1.8 percent with evidence of previous or undiagnosed SARS-CoV-2 virus infection. Thus, accounting for both diagnosed and undiagnosed infections, the study authors found that 4.6 percent of ED health care workers were infected with SARS-CoV-2, with 38 percent of those infections undiagnosed.
“Emergency departments were often the first point of access to the health care system for patients dealing with a SARS-CoV-2 infection,” said Walter Schrading, M.D., a professor in the UAB Department of Emergency Medicine and primary investigator at UAB for the study. “Additionally, a number of routine procedures in emergency departments, such as intubations and CPR, present an increased risk of transmission of the virus to health care workers. The low volume of infections noted in health care workers is a testament to the precautions and safeguards established by hospitals such as UAB.”
Schrading points out that as many as 60 percent of the small number of those with undiagnosed infection were asymptomatic, and thus unaware they carried the virus.
“Undiagnosed SARS-CoV-2 infection may pose substantial risk for transmission to other staff and patients,” Schrading said. “This is valuable baseline information that planners are using to cope with the current spike in infections and prepare for response to future potential outbreaks.”
Schrading enrolled 80 ED personnel at UAB into the study — 40 physicians, 20 nurses, and 20 non-clinical staff such as social workers or case managers.
The preliminary results of the study are presented in Annals of Emergency Medicine.