COVID 19: Report documents exposures of U.S. health worker infections

Duration of time with patient, presence during aerosol-generating procedures more common among infected health workers

One of the patients who was examined and subsequently admitted to a Solano County, California hospital on Feb. 15 would later be thought to be the first to have contracted the virus causing COVID-19 without a known source of exposure. But that day, U.S. infections were still considered necessarily linked to overseas travel or contact with a known infected person, and the virus that by then had spread around the world was not considered. Not one of the health care providers exposed to the patient was aware of their risk.

The day before, China had been confirmed that at least 1,716 health workers had been infected with SARS-CoV-2, and had COVID-19, while the U.S. Centers for Disease Control and Prevention had acknowledged problems with the diagnostic test the agency had sent to all 50 states and overseas. But it wouldn't be until more than two weeks later that the CDC would report what officials then called the first health worker infection, in the midst of a still unrecognized outbreak across a Seattle, Washington nursing home.

None of the health care providers caring for the patient at the California hospital where the patient was first admitted wore the personal protective equipment expressly recommended for COVID-19, including eye protection, gowns, N95 respirators or powered air-purifying respirators. It wasn't until four days after the patient had been transferred to a second hospital that test results confirmed the patient's illness was COVID-19. Within two weeks more than a third of 121 workers exposed to the patient at the first hospital were tested for the virus after showing symptoms. Three of them were confirmed to have it.

Presence during "aerosol-generating procedures" including nebulizer treatments, bilevel positive airway pressure (BiPAP) ventilation, endotracheal intubation and bronchoscopy, was more common among the infected than the uninfected health workers study examining exposures of 37 of the health workers, including the three infected, found. Longer durations of time in the patient's presence also were more common among the infected, one having been with the patient for a total of three hours while the patient was on BiPAP, another, while not present during an aerosol generating procedure, having reported a total of two hours with the patient.

The opportunity to examine the risks of those health care workers was valuable, a summary of the study in the April 17 Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report says, because in the time since, the numbers and sources of exposures have grown to numbers more challenging to analyze.

By the end of the first week of April, more than 9,000 COVID-19 cases had been confirmed among health workers, but with the health worker status of only 16% of all confirmed cases known, that is likely a vast underestimate, an accompanying MMWR summary says. While most were not hospitalized, severe outcomes, that included the deaths of 27 health care providers at that point, spanned age groups.