the staff of the Ridgewood blog
Ridgewood Nj, according to Johns Hopkins Center for Health Security the use and availability of face coverings, including for the general public and for healthcare workers, has been one of the major ongoing storylines over the course of the pandemic. Researchers continue to evaluate the role of masks and other face coverings in mitigating SARS-CoV-2 transmission, and hospitals and health systems in the US (and likely elsewhere) continue to struggle to maintain sufficient supply of respirators and surgical masks that are critical for protecting healthcare workers and patients.
Researchers from the University of California Davis and the Icahn School of Medicine at Mount Sinai (New York) published findings from a study to evaluate the ability of various mask types in reducing exhaled respiratory droplets. The study, published in Scientific Reports (a Nature journal), evaluated several different mask types, including N95 and KN95 respirators (vented and unvented; not fit-tested), surgical masks, and homemade cloth masks (single and double-layer). Measurements for respiratory droplets were taken while participants breathed, spoke, coughed, and chewed, and additional measurements were taken before and after washing cloth masks. The respirators and surgical masks exhibited a statistically significant decrease in respiratory droplets, whereas the homemade t-shirt masks did not. Notably, the cloth masks resulted in an increase in droplets in some instances, similar to results from a previous study that found increased droplets for neck gaiters. The researchers determined that cloth masks have the potential to shed cloth particles as the material breaks down, which could contribute to the volume of airborne particles. The current study only evaluated paper towel and t-shirt material for the homemade masks, and further research is needed to better characterize the effects of different types of cloth and mask construction. The researchers also note that the sampling methodology did not account for droplets that escape around the edges of the masks.
An investigation conducted by ECRI—”an independent, nonprofit organization improving the safety, quality, and cost-effectiveness of care across all healthcare settings”—found that KN95 respirators originating in China may not provide sufficient protection for healthcare workers. During the pandemic, KN95 respirators have been used to supplement limited supply of NIOSH-certified N95 respirators, including in healthcare settings. In theory, KN95 respirators should provide similar filtration capabilities as the certified N95 respirators; however, ECRI found that some KN95 respirators do not meet the same filtering standards. The researchers tested 200 respirators across 15 different models, and 60-70% of the KN95 masks imported from China did not filter 95% of airborne particles like they should. Notably, it may be difficult to distinguish between KN95 and N95 respirators visually; however, many of the tested KN95 respirators utilize ear loops, as opposed to elastic straps that go around the head and neck, which do not provide an adequate seal between the respirator and the wearer’s face. ECRI recommended that hospitals and health systems purchasing KN95 respirators conduct tests to ensure the products are providing appropriate protection. In April, the US FDA issued an Emergency Use Authorization (EUA) for non-NIOSH-certified respirators, and it has issued several updates since then to address quality control issues with imported products, including a list of products no longer authorized under the EUA due to inadequate performance.