Reposting because of a site error which deleted it instead of moving it:
study quantifies effect of mask, distance
https://www.medscape.com/viewarticle/931551
>
COVID-19: Distancing Works, N95 Respirators Work Better
Richard Mark Kirkner
June 01, 2020
snip
The meta-analysis involved pooled estimates from 44 comparative studies with 25,697 participants, including seven studies of COVID-19 with 6,674 participants. None of the studies included in the meta-analysis were randomized clinical trials.
A subanalysis of 29 unadjusted and 9 adjusted studies found that the absolute risk of infection in proximity to an exposed individual was 12.8% at 1 m and 2.6% at 2 m. The risk remained constant even when the six COVID-19 studies in this subanalysis were isolated and regardless of being in a health care or non–health-care setting. Each meter of increased distance resulted in a doubling in the change in relative risk (P = .041).
The study also identified what Dr. Chu and colleagues characterized as a "large reduction" in infection risk with the use of both N95 or similar respirators or face masks, with an adjusted risk of infection of 3.1% with a face covering vs. a 17.4% without. The researchers also found a stronger association in health care settings vs. non–health care settings, with a relative risk of 0.3 vs. 0.56, respectively (P = .049). The protective effect of N95 or similar respirators was greater than other masks, with adjusted odds ratios of 0.04 vs. 0.33 (P = .09).
Eye protection was found to reduce the risk of infection to 5.5% vs. 16% without eye protection.
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"The Centers for Disease Control and Prevention initially recommended N95s for health workers treating COVID-19 patients, but later downgraded this to surgical masks and even cloth masks and bandannas when there was a supply shortage," she said. "This study shows that N95s are superior masks and should prompt a review of guidelines that recommend anything less for health workers."
Recommending anything less than N95 masks for health workers is like sending troops into battle "unarmed or with bows and arrows against a fully armed enemy," she said. "We are not talking about a device that costs hundreds or thousands of dollars; a N95 costs less than a dollar to produce. All that is needed to address the supply shortage is political will."
snip
study quantifies effect of mask, distance
https://www.medscape.com/viewarticle/931551
>
COVID-19: Distancing Works, N95 Respirators Work Better
Richard Mark Kirkner
June 01, 2020
snip
The meta-analysis involved pooled estimates from 44 comparative studies with 25,697 participants, including seven studies of COVID-19 with 6,674 participants. None of the studies included in the meta-analysis were randomized clinical trials.
A subanalysis of 29 unadjusted and 9 adjusted studies found that the absolute risk of infection in proximity to an exposed individual was 12.8% at 1 m and 2.6% at 2 m. The risk remained constant even when the six COVID-19 studies in this subanalysis were isolated and regardless of being in a health care or non–health-care setting. Each meter of increased distance resulted in a doubling in the change in relative risk (P = .041).
The study also identified what Dr. Chu and colleagues characterized as a "large reduction" in infection risk with the use of both N95 or similar respirators or face masks, with an adjusted risk of infection of 3.1% with a face covering vs. a 17.4% without. The researchers also found a stronger association in health care settings vs. non–health care settings, with a relative risk of 0.3 vs. 0.56, respectively (P = .049). The protective effect of N95 or similar respirators was greater than other masks, with adjusted odds ratios of 0.04 vs. 0.33 (P = .09).
Eye protection was found to reduce the risk of infection to 5.5% vs. 16% without eye protection.
snip
"The Centers for Disease Control and Prevention initially recommended N95s for health workers treating COVID-19 patients, but later downgraded this to surgical masks and even cloth masks and bandannas when there was a supply shortage," she said. "This study shows that N95s are superior masks and should prompt a review of guidelines that recommend anything less for health workers."
Recommending anything less than N95 masks for health workers is like sending troops into battle "unarmed or with bows and arrows against a fully armed enemy," she said. "We are not talking about a device that costs hundreds or thousands of dollars; a N95 costs less than a dollar to produce. All that is needed to address the supply shortage is political will."
snip
