. Update to ‘living review’ summarizes latest evidence on mask use among laypersons and health care workers
Researchers from Oregon Health & Sciences University published a fourth update to their living rapid review of evidence evaluating the use of masks among lay persons in the community and health care workers for preventing the spread of respiratory virus infections, including SARS-CoV-2, the virus that causes COVID-19. The update includes 739 citations that were published from early October to early December 2020 using the same search strategies as the original review. One study on the use of masks and the prevention of SARS-CoV-2 infection in a community setting (the DANMASK trial) and two studies in health care settings were added for the update.
Read the full text: https:/
/ www. acpjournals. org/ doi/ 10. 7326/ L20-1429.
The DANMASK trial, a good-quality, open-label trial of 6,024 community-dwelling adults in Denmark evaluated the effects of wearing a surgical mask outside of the house, at a time when mask wearing in the community was neither recommended nor common. The trial found that the incidence of SARS-CoV-2 infection among participants was 2.0%. Mask use versus no mask use was associated with a small, non-statistically significant reduction in risk for SARS-CoV-2 infection. The trial was not designed to assess the effects of mask use as source control; in addition, high adherence to other infection control measures (for example, physical distancing and handwashing) could have attenuated potential benefits.
The evidence on mask use in health care settings and risk for SARS-CoV-2 infection was previously assessed as insufficient on the basis of three studies with methodological limitations. Two new cohort studies, both done in the United States, reported on mask use in health care settings. One study of 16,397 health care workers and first responders (86% health care workers) found that use of an N95 or surgical mask all of the time versus not all of the time was associated with a decreased risk for infection. In the second study, done in 20,614 asymptomatic health care workers, risk for infection was reduced with any mask use versus no mask use. An N95 mask was associated with decreased risk versus a surgical mask. However, both studies had methodological limitations, so evidence for various comparisons about mask use in health care settings and risk for SARS-CoV-2 remains insufficient
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