The Centers for Disease Control and Prevention (CDC) and Michigan Department of Health and Human Services surveyed health care personnel in 27 hospitals and 7 medical control agencies that coordinate emergency medical services in the Detroit metropolitan area. Of 16,397 participants, 6.9% had COVID-19 antibodies (although only 2.7% reported a history of a positive real-time transcription polymerase chain reaction test); however, participants had about 6 times the odds of exposure to the virus at home when compared with the workplace. Of those who reported close contact (within 6 feet) of a person with confirmed COVID-19 for ≥ 10 minutes, seroprevalence was highest among those with exposure to a household member (34.3%).
The survey revealed a pattern that suggested community acquisition was a common underlying factor of infection risk, the researchers say. Workers were only more vulnerable at home and when they were closer to the metropolitan center. Seropositivity was more common within 9 miles of Detroit’s center, regardless of occupation and health care setting. The farther away from the center, the lower the seroprevalence.
By work location, seroprevalence was highest among participants who worked in hospital wards (8.8%) and lowest among those in police departments (3.9%). In hospitals, participants working in wards and EDs had higher seropositivity (8.8% and 8.1%, respectively) than did those in ICUs and ORs (6.1% and 4.5%, respectively). Nurses and nurse assistants were more likely to be seropositive than physicians. Nurse assistants had the highest incidence, regardless of where they worked.
Reducing community spread through population-based measures may directly protect healthcare workers on 2 fronts, the researchers say: reduced occupational exposure as a result of fewer infected patients in the less controlled workplace setting such as the ED, and reduced exposure in their homes and communities.