Про эффективность масок
Подборка выдержек из нескольких статей за последний год.
Using data relevant to COVID-19 dynamics in the US states of New York and Washington, suggest that broad adoption of even relatively ineffective face masks may meaningfully reduce community transmission of COVID-19 and decrease peak hospitalizations and deaths. Moreover, mask use decreases the effective transmission rate in nearly linear proportion to the product of mask effectiveness (as a fraction of potentially infectious contacts blocked) and coverage rate (as a fraction of the general population), while the impact on epidemiologic outcomes (death, hospitalizations) is highly nonlinear, indicating masks could synergize with other non-pharmaceutical measures. Notably, masks are found to be useful with respect to both preventing illness in healthy persons and preventing asymptomatic transmission
Our results suggest use of face masks by the general public is potentially of high value in curtailing community transmission and the burden of the pandemic. The community-wide benefits are likely to be greatest when face masks are used in conjunction with other non-pharmaceutical practices (such as social-distancing), and when adoption is nearly universal (nation-wide) and compliance is high.
A total of 21 studies met our inclusion criteria. Meta-analyses suggest that mask use provided a significant protective effect (OR=0.35 and 95% CI=0.24-0.51). Use of masks by healthcare workers (HCWs) and non-healthcare workers (Non-HCWs) can reduce the risk of respiratory virus infection by 80% (OR=0.20, 95% CI=0.11-0.37) and 47% (OR=0.53, 95% CI=0.36-0.79). The protective effect of wearing masks in Asia (OR=0.31) appeared to be higher than that of Western countries (OR=0.45). Masks had a protective effect against influenza viruses (OR=0.55), SARS (OR=0.26), and SARS-CoV-2 (OR=0.04). In the subgroups based on different study designs, protective effects of wearing mask were significant in cluster randomized trials and observational studies.
This study adds additional evidence of the enhanced protective value of masks, we stress that the use masks serve as an adjunctive method regarding the COVID-19 outbreak.
In contrast, wearing face masks is a highly effective strategy to reduce the spread of infection. Our results are general, and suggest that, even when a large fraction of infected individuals is asymptomatic, mask wearing is the most effective strategy to control virus spread and alleviate the impact of COVID-19 outbreak, particularly when combined with conditions of partial SD compatible with the function of society.
Findings Our search identified 35 studies, including 3 randomised controlled trials (RCTs) (4017 patients), 10 comparative studies (18984 patients), 13 predictive models, 9 laboratory experimental studies. For reducing infection rates, the estimates of cluster-RCTs were in favour of wearing face masks versus no mask, but not at statistically significant levels (adjusted OR 0.90, 95%CI 0.78-1.05). Similar findings were reported in observational studies. Mathematical models indicated an important decrease in mortality when the population mask coverage is near-universal, regardless of mask efficacy. In the best-case scenario, when the mask efficacy is at 95%, the R0 can fall to 0.99 from an initial value of 16.90. Levels of mask filtration efficiency were heterogeneous, depending on the materials used (surgical mask: 45-97%). One laboratory study suggested a viral load reduction of 0.25 (95%CI 0.09-0.67) in favour of mask versus no mask.
The Executive Order on face mask use is estimated to avert 99,517 (95% CIs: 72,723-126,312) COVID-19 infections and 7,978 (5,692-10,265) deaths in NYC. If the Executive Order was implemented one week earlier (on April 10), the averted infections and deaths would be 111,475 (81,593-141,356) and 9,017 (6,446-11,589), respectively. If the Executive Order was implemented two weeks earlier (on April 3 when the Centers for Disease Control and Prevention recommended face mask use), the averted infections and deaths would be 128,598 (94,373-162,824) and 10,515 (7,540-13,489), respectively.
New York’s Executive Order on face mask use is projected to have significantly reduced the spread of COVID-19 in NYC. Implementing the Executive Order at an earlier date would avert even more COVID-19 infections and deaths.
We estimate the impact of indoor face mask mandates and other non-pharmaceutical interventions (NPI) on COVID-19 case growth in Canada. Mask mandate introduction was staggered from mid-June to mid-August 2020 in the 34 public health regions in Ontario, Canada’s largest province by population. Using this variation, we find that mask mandates are associated with a 22 percent weekly reduction in new COVID-19 cases, relative to the trend in absence of mandate.
our results indicate that mandating mask wearing in indoor public places can be a powerful policy tool to slow the spread of COVID-19.
We show that mask mandates are associated with a statistically significant decrease in new cases (-3.55 per 100K), deaths (-0.13 per 100K), and the proportion of hospital admissions (-2.38 percentage points) up to 40 days after the introduction of mask mandates both at the state and county level.
Lastly, using a large novel survey dataset of almost half a million people in 68 countries, we introduce the novel results that community mask adherence and community attitudes towards masks are associated with a reduction in COVID-19 cases and deaths
Results 991 schools had restarted fall sports, representing 152,484 athletes on 5,854 teams. 2,565 cases of COVID-19 were reported, representing a case rate of 1,682 cases per 100,000 athletes and an incidence rate of 24.6 cases per 100,000 player-days.
Face mask use was associated with a decreased incidence in girls’ volleyball (IRR=0.53 [0.37-0.73], p<0.001), boys’ basketball (IRR=0.53 [0.33-0.83], p=0.008) and girls’ basketball (IRR=0.36 [0.19-0.63], p<0.001), and approached statistical significance in football (IRR=0.79 [0.59-1.04], p=0.10) and cheer/dance (IRR=0.75 [0.53-1.03], p=0.081).
Single fabric layers blocked a range of ultrafine particles. When fabrics were layered, significantly more ultrafine particles were filtered. Nonwoven fusible interfacing significantly increased filtration.
Our findings suggest that face masks made from layered common fabric can help filter ultrafine particles and provide some protection for the wearer when commercial facemasks are unavailable.
еще экспериментальные данные:
Experimental efficacy of the face shield and the mask against emitted and potentially received particles
International Journal of Environmental Research and Public Health doi: 10.3390/ijerph18041942
We tested different configurations in an experimental setup with manikin heads wearing masks (surgical type I), face shields (22.5 cm high with overhang under the chin of 7 cm and circumference of 35 cm) on an emitter or a receiver manikin head, or both. The mannequins were face to face, 25 cm apart, with an intense particle emission (52.5 l/min) for 30 seconds. In our experimental conditions, when the receiver alone wore a protection, the face shield was more effective (reduction factor=54.8%), while reduction was lower with a mask (reduction factor=21.8%) (p=0.002). The wearing of a protective device by the emitter alone reduced the level of received particles by 96.8% for both the mask and face shield (p= NS). When both the emitter and receiver manikin heads wore a face shield, the ensuing double protection allowed for better results: 98% reduction for the face shields vs. 97.3% for the masks (p=0.01).
We tested different configurations in an experimental setup with manikin heads wearing masks (surgical type I), face shields (22.5 cm high with overhang under the chin of 7 cm and circumference of 35 cm) on an emitter or a receiver manikin head, or both. The mannequins were face to face, 25 cm apart, with an intense particle emission (52.5 l/min) for 30 seconds. In our experimental conditions, when the receiver alone wore a protection, the face shield was more effective (reduction factor=54.8%), while reduction was lower with a mask (reduction factor=21.8%) (p=0.002). The wearing of a protective device by the emitter alone reduced the level of received particles by 96.8% for both the mask and face shield (p= NS). When both the emitter and receiver manikin heads wore a face shield, the ensuing double protection allowed for better results: 98% reduction for the face shields vs. 97.3% for the masks (p=0.01).
или
At the most penetrating particle size, the vacuum bag, microfiber cloth, and surgical mask had material filtration efficiencies >50%,
these efficiencies increased rapidly with particle size, and many materials had efficiencies >50% at 2 μm and >75% at 5 μm
Results In 20 participants, sound intensity was 71 Decibels (dB) for speaking and 85 dB for singing (p<0.001). MVM was similar for all tasks with no clear hierarchy between vocal tasks or people and >85% reduction wearing face masks. Droplet transmission varied widely, particularly for singing. Masks decreased TADN by 99% (p<0.001) and MDN by 98% (p<0.001) for singing and 86-97% for other tasks. Masks reduced variance by up to 48%. When wearing a mask, neither singing task transmitted more droplets than exhaling.
Wide variation exists for droplet production. This significantly reduced when wearing face masks. Singing during religious worship wearing a face mask appears as safe as exhaling or talking
Using data relevant to COVID-19 dynamics in the US states of New York and Washington, suggest that broad adoption of even relatively ineffective face masks may meaningfully reduce community transmission of COVID-19 and decrease peak hospitalizations and deaths. Moreover, mask use decreases the effective transmission rate in nearly linear proportion to the product of mask effectiveness (as a fraction of potentially infectious contacts blocked) and coverage rate (as a fraction of the general population), while the impact on epidemiologic outcomes (death, hospitalizations) is highly nonlinear, indicating masks could synergize with other non-pharmaceutical measures. Notably, masks are found to be useful with respect to both preventing illness in healthy persons and preventing asymptomatic transmission
Our results suggest use of face masks by the general public is potentially of high value in curtailing community transmission and the burden of the pandemic. The community-wide benefits are likely to be greatest when face masks are used in conjunction with other non-pharmaceutical practices (such as social-distancing), and when adoption is nearly universal (nation-wide) and compliance is high.
A total of 21 studies met our inclusion criteria. Meta-analyses suggest that mask use provided a significant protective effect (OR=0.35 and 95% CI=0.24-0.51). Use of masks by healthcare workers (HCWs) and non-healthcare workers (Non-HCWs) can reduce the risk of respiratory virus infection by 80% (OR=0.20, 95% CI=0.11-0.37) and 47% (OR=0.53, 95% CI=0.36-0.79). The protective effect of wearing masks in Asia (OR=0.31) appeared to be higher than that of Western countries (OR=0.45). Masks had a protective effect against influenza viruses (OR=0.55), SARS (OR=0.26), and SARS-CoV-2 (OR=0.04). In the subgroups based on different study designs, protective effects of wearing mask were significant in cluster randomized trials and observational studies.
This study adds additional evidence of the enhanced protective value of masks, we stress that the use masks serve as an adjunctive method regarding the COVID-19 outbreak.
In contrast, wearing face masks is a highly effective strategy to reduce the spread of infection. Our results are general, and suggest that, even when a large fraction of infected individuals is asymptomatic, mask wearing is the most effective strategy to control virus spread and alleviate the impact of COVID-19 outbreak, particularly when combined with conditions of partial SD compatible with the function of society.
Findings Our search identified 35 studies, including 3 randomised controlled trials (RCTs) (4017 patients), 10 comparative studies (18984 patients), 13 predictive models, 9 laboratory experimental studies. For reducing infection rates, the estimates of cluster-RCTs were in favour of wearing face masks versus no mask, but not at statistically significant levels (adjusted OR 0.90, 95%CI 0.78-1.05). Similar findings were reported in observational studies. Mathematical models indicated an important decrease in mortality when the population mask coverage is near-universal, regardless of mask efficacy. In the best-case scenario, when the mask efficacy is at 95%, the R0 can fall to 0.99 from an initial value of 16.90. Levels of mask filtration efficiency were heterogeneous, depending on the materials used (surgical mask: 45-97%). One laboratory study suggested a viral load reduction of 0.25 (95%CI 0.09-0.67) in favour of mask versus no mask.
The Executive Order on face mask use is estimated to avert 99,517 (95% CIs: 72,723-126,312) COVID-19 infections and 7,978 (5,692-10,265) deaths in NYC. If the Executive Order was implemented one week earlier (on April 10), the averted infections and deaths would be 111,475 (81,593-141,356) and 9,017 (6,446-11,589), respectively. If the Executive Order was implemented two weeks earlier (on April 3 when the Centers for Disease Control and Prevention recommended face mask use), the averted infections and deaths would be 128,598 (94,373-162,824) and 10,515 (7,540-13,489), respectively.
New York’s Executive Order on face mask use is projected to have significantly reduced the spread of COVID-19 in NYC. Implementing the Executive Order at an earlier date would avert even more COVID-19 infections and deaths.
We estimate the impact of indoor face mask mandates and other non-pharmaceutical interventions (NPI) on COVID-19 case growth in Canada. Mask mandate introduction was staggered from mid-June to mid-August 2020 in the 34 public health regions in Ontario, Canada’s largest province by population. Using this variation, we find that mask mandates are associated with a 22 percent weekly reduction in new COVID-19 cases, relative to the trend in absence of mandate.
our results indicate that mandating mask wearing in indoor public places can be a powerful policy tool to slow the spread of COVID-19.
We show that mask mandates are associated with a statistically significant decrease in new cases (-3.55 per 100K), deaths (-0.13 per 100K), and the proportion of hospital admissions (-2.38 percentage points) up to 40 days after the introduction of mask mandates both at the state and county level.
Lastly, using a large novel survey dataset of almost half a million people in 68 countries, we introduce the novel results that community mask adherence and community attitudes towards masks are associated with a reduction in COVID-19 cases and deaths
Results 991 schools had restarted fall sports, representing 152,484 athletes on 5,854 teams. 2,565 cases of COVID-19 were reported, representing a case rate of 1,682 cases per 100,000 athletes and an incidence rate of 24.6 cases per 100,000 player-days.
Face mask use was associated with a decreased incidence in girls’ volleyball (IRR=0.53 [0.37-0.73], p<0.001), boys’ basketball (IRR=0.53 [0.33-0.83], p=0.008) and girls’ basketball (IRR=0.36 [0.19-0.63], p<0.001), and approached statistical significance in football (IRR=0.79 [0.59-1.04], p=0.10) and cheer/dance (IRR=0.75 [0.53-1.03], p=0.081).
Single fabric layers blocked a range of ultrafine particles. When fabrics were layered, significantly more ultrafine particles were filtered. Nonwoven fusible interfacing significantly increased filtration.
Our findings suggest that face masks made from layered common fabric can help filter ultrafine particles and provide some protection for the wearer when commercial facemasks are unavailable.
еще экспериментальные данные:
Experimental efficacy of the face shield and the mask against emitted and potentially received particles
International Journal of Environmental Research and Public Health doi: 10.3390/ijerph18041942
We tested different configurations in an experimental setup with manikin heads wearing masks (surgical type I), face shields (22.5 cm high with overhang under the chin of 7 cm and circumference of 35 cm) on an emitter or a receiver manikin head, or both. The mannequins were face to face, 25 cm apart, with an intense particle emission (52.5 l/min) for 30 seconds. In our experimental conditions, when the receiver alone wore a protection, the face shield was more effective (reduction factor=54.8%), while reduction was lower with a mask (reduction factor=21.8%) (p=0.002). The wearing of a protective device by the emitter alone reduced the level of received particles by 96.8% for both the mask and face shield (p= NS). When both the emitter and receiver manikin heads wore a face shield, the ensuing double protection allowed for better results: 98% reduction for the face shields vs. 97.3% for the masks (p=0.01).
We tested different configurations in an experimental setup with manikin heads wearing masks (surgical type I), face shields (22.5 cm high with overhang under the chin of 7 cm and circumference of 35 cm) on an emitter or a receiver manikin head, or both. The mannequins were face to face, 25 cm apart, with an intense particle emission (52.5 l/min) for 30 seconds. In our experimental conditions, when the receiver alone wore a protection, the face shield was more effective (reduction factor=54.8%), while reduction was lower with a mask (reduction factor=21.8%) (p=0.002). The wearing of a protective device by the emitter alone reduced the level of received particles by 96.8% for both the mask and face shield (p= NS). When both the emitter and receiver manikin heads wore a face shield, the ensuing double protection allowed for better results: 98% reduction for the face shields vs. 97.3% for the masks (p=0.01).
или
At the most penetrating particle size, the vacuum bag, microfiber cloth, and surgical mask had material filtration efficiencies >50%,
these efficiencies increased rapidly with particle size, and many materials had efficiencies >50% at 2 μm and >75% at 5 μm
Results In 20 participants, sound intensity was 71 Decibels (dB) for speaking and 85 dB for singing (p<0.001). MVM was similar for all tasks with no clear hierarchy between vocal tasks or people and >85% reduction wearing face masks. Droplet transmission varied widely, particularly for singing. Masks decreased TADN by 99% (p<0.001) and MDN by 98% (p<0.001) for singing and 86-97% for other tasks. Masks reduced variance by up to 48%. When wearing a mask, neither singing task transmitted more droplets than exhaling.
Wide variation exists for droplet production. This significantly reduced when wearing face masks. Singing during religious worship wearing a face mask appears as safe as exhaling or talking