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Tag: masks
October 30, 2020
Association of County-Wide Mask Ordinances with Reductions in Daily CoVID-19 Incident Case Growth in a Midwestern Region Over 12 Weeks
[Pre-print, not peer-reviewed] Missouri counties with mask mandates had a daily percent COVID-19 growth rate that was 32% lower than the growth rate in counties without mask mandates, based on a population-based quasi-experimental longitudinal study conducted from June to September. In the 3 weeks before mandatory mask mandates were instated, the average daily percent increase…
Peripheral Oxygen Saturation in Older Persons Wearing Nonmedical Face Masks in Community Settings
Wearing a 3-layer non-medical face mask was not associated with a decline in oxygen saturation among adults over 65 in a small (n=25) crossover study. Study participants were provided with a mask and pulse oximeter and were instructed to measure their peripheral oxygen saturation (Spo2) three times, twenty minutes apart for one hour before, one…
October 28, 2020
Effects of New York’s Executive Order on Face Mask Use on COVID-19 Infections and Mortality A Modeling Study
[Pre-print, not peer reviewed] According to estimates from a modeling study, the Executive Order issued by New York State mandating mask use reduced the number of COVID-19 infections by 99,517 (95% CIs: 72,723-126,312) and COVID-related deaths by 7,978 (5,692-10,265). If the Executive Order were implemented earlier, greater numbers of infections and deaths would have been…
October 12, 2020
Global Projections of Potential Lives Saved from COVID-19 through Universal Mask Use
[Pre-print, not peer reviewed] An IHME analysis found that universal mask use could lead to a reduction of 815,600 (95% UI 430,600 – 1,491,000) deaths from COVID-19 globally between August 26th 2020 and January 1st 2021. The analysis used meta-regression of 40 studies measuring the impact of mask use on respiratory viral infections, as well…
October 7, 2020
Efficacy of Face Masks Neck Gaiters and Face Shields for Reducing the Expulsion of Simulated Cough-Generated Aerosols
[Pre-print, not peer-reviewed] Face coverings were found to be more effective than face shields at blocking the small aerosol particles propelled by a cough aerosol simulator. The efficacy of blocking aerosols was 99% with an N95 respirator, 59% with a procedure mask, 51% with a 3-ply cloth face mask, 47% with a polyester neck gaiter…
Comparing Associations of State Reopening Strategies with COVID-19 Burden
Comparing trends in COVID-19 cases over time between states with differing approaches to mask mandates indicates that mask use and other mitigation measures can counteract increases in COVID-19 cases and deaths in response to reopening of businesses. Based on a interrupted time series quasi-experimental study, in states that reopened indoor dining rooms before implementing a…
September 25, 2020
Quantifying the impact of quarantine duration on COVID-19 transmission
[Pre-print, not peer reviewed] In a modeling study, quarantining an infected traced contact for 10 days was estimated to prevent 75-99% of their onward transmission. In the scenario of a contact being infected on a return flight, a 10 day quarantine was estimated to prevent 99% of onward transmission. Ashcroft et al. (Sept 25, 2020)….
Efficacy of masks and face coverings in controlling outward aerosol particle emission from expiratory activities
Surgical masks and unvented KN95 respirators reduce outward particle emissions by 90% during speaking and 74% during coughing, compared to wearing no mask. These masks decreased the outward particle emission of a coughing superemitter who produced up to two orders more expiratory particles than average. Due to experimental confounding, the study was not able to…
August 27, 2020
Effectiveness of Surgical, KF94, and N95 Respirator Masks in Blocking SARS-CoV-2: A Controlled Comparison in 7 Patients
Kim et al. detected SARS-CoV-2 RNA by PCR on petri dishes placed in front of patients with SARS-CoV-2 infection in 3/7 patients who coughed while wearing a surgical mask, but in 0/7 petri dishes from similar experiments with the same patients wearing N95 masks and similar KF94 masks. Additionally, researchers detected viral RNA in swabs…
August 25, 2020
Mask Wearing and Control of SARS-CoV-2 Transmission in the United States
[pre-print, not peer-reviewed] Using weekly longitudinal survey results on face mask wearing, US states with higher levels of face mask wearing were more likely to have a SARS-CoV-2 effective reproductive number (Rt) less than 1, which would lead to control of community transmission. A 10% increase in mask wearing was associated with a higher likelihood…
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