Study population and setting
On March 24, 2020, a tertiary care facility in Alabama (United States) implemented a policy requiring healthcare workers (HCWs) to use ASTN level-1 procedural masks and all other patients to wear masks. Patients were designated as persons under investigation (PUI) if they showed at least one of the following four symptoms: fever, cough, shortness of breath, or unresponsive. HCW high-risk exposures included episodes where the provider and potential exposure source (e.g., patient, employee, community member) were not wearing masks and exposures to an aerosol-generating procedure without appropriate protective equipment. To compare the effect of universal testing and masking on HCW’s high-risk exposures, the investigators modeled the rate of providers’ high-risk exposures (as a rate per 100 patient-days) in the periods before (March 11 – 25) and after the introduction of universal masking (March 26 – April 5) and universal testing (April 6 – May 19).
Summary of Main Findings
Universal masking was associated with a 73% reduction in the rate of HCW exposures to patients without masks but a marginal (41%) reduction in HCW exposures to aerosol-generating procedures without appropriate PPE. Compared to universal masking alone, universal testing was associated with an additional 77% reduction in the rate of HCW exposure to patients without masks and 56% reduction in the rate of HCW exposures to aerosol-generating procedures without appropriate PPE.
The authors measured changes in high-risk exposure rates among HCWs over time in order to make inferences about the potential impact of universal masking and testing on COVID-19 exposures.
The denominator (e.g., patient-days) of the primary outcome measure does not account for differences in total potential exposure time (e.g., days working at the hospital, total number of contacts) contributed by HCWs. Because self-reported exposures could include contact with persons in the health facility and the community, observed reductions in the exposure rate could also be attributed to secular policy changes (e.g., shelter-in-place orders, school and business closures) that could result in lower patient volume in the facility as well as reduced exposures in the community. Additionally, the authors did not enumerate the number of healthcare workers reporting any high-risk exposure as a proportion of all HCWs, making it difficult to discern whether exposures were concentrated in specific providers or were more universal. Lastly, this study did not assess/report on SARS-CoV-2 infection among the HCWs in this study; thus, it is unclear if the masking and testing policies actually reduced transmission of SARS-CoV-2 among HCWs.
This paper highlights the added benefits of a universal testing/isolation algorithm to reduced high-risk exposures among healthcare workers in the context of universal masking.
This review was posted on: 26 October 2020