Response to 'MacIntyre et al., 2020: A rapid systematic review of the efficacy of face masks and respirators against coronaviruses and other respiratory transmissible viruses for the community, healthcare workers and sick patient'.
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ABSTRACT:
SUBMITTER: Haslam A
PROVIDER: S-EPMC7434616 | biostudies-literature | 2020 Nov
REPOSITORIES: biostudies-literature
Publications
Response to 'MacIntyre et al., 2020: A rapid systematic review of the efficacy of face masks and respirators against coronaviruses and other respiratory transmissible viruses for the community, healthcare workers and sick patient'.
International journal of nursing studies 20200819
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Project description:We discuss the results on improving the generalizability of individualized treatment rule following the work in Kallus [1] and Mo et al. [5]. We note that the advocated weights in Kallus [1] are connected to the efficient score of the contrast function. We further propose a likelihood-ratio-based method (LR-ITR) to accommodate covariate shifts, and compare it to the CTE-DR-ITR method proposed in Mo et al. [5]. We provide the upper-bound on the risk function of the target population when both the covariate shift and the contrast function shift are present. Numerical studies show that LR-ITR can outperform CTE-DR-ITR when there is only covariate shift.
| S-EPMC8409173 | biostudies-literature
Project description:Face coverings are a key component of preventive health measure strategies to mitigate the spread of respiratory illnesses. In this study five groups of masks were investigated that are of particular relevance to the SARS-CoV-2 pandemic: re-usable, fabric two-layer and multi-layer masks, disposable procedure/surgical masks, KN95 and N95 filtering facepiece respirators. Experimental work focussed on the particle penetration through mask materials as a function of particle diameter, and the total inward leakage protection performance of the mask system. Geometric mean fabric protection factors varied from 1.78 to 144.5 for the fabric two-layer and KN95 materials, corresponding to overall filtration efficiencies of 43.8% and 99.3% using a flow rate of 17 L/min, equivalent to a breathing expiration rate for a person in a sedentary or standing position conversing with another individual. Geometric mean total inward leakage protection factors for the 2-layer, multi-layer and procedure masks were <2.3, while 6.2 was achieved for the KN95 masks. The highest values were measured for the N95 group at 165.7. Mask performance is dominated by face seal leakage. Despite the additional filtering layers added to cloth masks, and the higher filtration efficiency of the materials used in disposable procedure and KN95 masks, the total inward leakage protection factor was only marginally improved. N95 FFRs were the only mask group investigated that provided not only high filtration efficiency but high total inward leakage protection, and remain the best option to protect individuals from exposure to aerosol in high risk settings. The Mask Quality Factor and total inward leakage performance are very useful to determine the best options for masking. However, it is highly recommended that testing is undertaken on prospective products, or guidance is sought from impartial authorities, to confirm they meet any implied standards.
| S-EPMC8494377 | biostudies-literature
Project description:ObjectiveWe aimed to examine the efficacy of medical masks and respirators in protecting against respiratory infections using pooled data from two homogenous randomised control clinical trials (RCTs).MethodsThe data collected on 3591 subjects in two similar RCTs conducted in Beijing, China, which examined the same infection outcomes, were pooled. Four interventions were compared: (i) continuous N95 respirator use, (ii) targeted N95 respirator use, (iii) medical mask use and (iv) control arm. The outcomes were laboratory-confirmed viral respiratory infection, influenza A or B, laboratory-confirmed bacterial colonisation and pathogens grouped by mode of transmission.ResultsRates of all outcomes were consistently lower in the continuous N95 and/or targeted N95 arms. In adjusted analysis, rates of laboratory-confirmed bacterial colonisation (RR 0.33, 95% CI 0.21-0.51), laboratory-confirmed viral infections (RR 0.46, 95% CI 0.23-0.91) and droplet-transmitted infections (RR 0.26, 95% CI 0.16-0.42) were significantly lower in the continuous N95 arm. Laboratory-confirmed influenza was also lowest in the continuous N95 arm (RR 0.34, 95% CI 0.10-1.11), but the difference was not statistically significant. Rates of laboratory-confirmed bacterial colonisation (RR 0.54, 95% CI 0.33-0.87) and droplet-transmitted infections (RR 0.43, 95% CI 0.25-0.72) were also lower in the targeted N95 arm, but not in medical mask arm.ConclusionThe results suggest that the classification of infections into droplet versus airborne transmission is an oversimplification. Most guidelines recommend masks for infections spread by droplets. N95 respirators, as "airborne precautions," provide superior protection for droplet-transmitted infections. To ensure the occupational health and safety of healthcare worker, the superiority of respirators in preventing respiratory infections should be reflected in infection control guidelines.
| S-EPMC5705692 | biostudies-literature
Project description:The COVID-19 pandemic presents a unique challenge to the healthcare community due to the high infectivity rate and need for effective personal protective equipment. Zinc oxide nanoparticles have shown promising antimicrobial properties and are recognized as a safe additive in many food and cosmetic products. This work presents a novel nanocomposite synthesis approach, which allows zinc oxide nanoparticles to be grown within textile and face mask materials, including melt-blown polypropylene and nylon-cotton. The resulting nanocomposite achieves greater than 3 log10 reduction (≥ 99.9%) in coronavirus titer within a contact time of 10 min, by disintegrating the viral envelope. The new nanocomposite textile retains activity even after 100 laundry cycles and has been dermatologist tested as non-irritant and hypoallergenic. Various face mask designs were tested to improve filtration efficiency and breathability while offering antiviral protection, with Claros' design reporting higher filtration efficiency than surgical masks (> 50%) for particles ranged 200 nm to 5 µm in size.
| S-EPMC8692499 | biostudies-literature
Project description:Familiarity with the use of face coverings to reduce the risk of respiratory disease has increased during the coronavirus pandemic; however, recommendations for their use outside of the pandemic remains limited. Here, we develop a modeling framework to quantify the potential health benefits of wearing a face covering or respirator to mitigate exposure to particulate air pollution. This framework accounts for the wide range of available face coverings and respirators, fit factors and efficacy, air pollution characteristics, and exposure-response data. Our modeling shows that N95 respirators offer robust protection against different sources of particulate matter, reducing exposure by more than a factor of 14 when worn with a leak rate of 5%. Synthetic-fiber masks offer less protection with a strong dependence on aerosol size distribution (protection factors ranging from 4.4 to 2.2), while natural-fiber and surgical masks offer reductions in the exposure of 1.9 and 1.7, respectively. To assess the ability of face coverings to provide population-level health benefits to wildfire smoke, we perform a case study for the 2012 Washington state fire season. Our models suggest that although natural-fiber masks offer minor reductions in respiratory hospitalizations attributable to smoke (2%-11%) due to limited filtration efficiency, N95 respirators and to a lesser extent surgical and synthetic-fiber masks may lead to notable reductions in smoke-attributable hospitalizations (22%-39%, 9%-24%, and 7%-18%, respectively). The filtration efficiency, bypass rate, and compliance rate (fraction of time and population wearing the device) are the key factors governing exposure reduction potential and health benefits during severe wildfire smoke events.
| S-EPMC8438762 | biostudies-literature
Project description:Root-secreted coumarins and the microbiota interact to improve iron nutrition in Arabidopsis. Harbort and Hashimoto et al. Cell Host & Microbe 2020
| PRJEB38663 | ENA
Project description:Within the current SARS-CoV-2 pandemic, personal protective equipment, including face masks, is one important tool to interrupt virus transmission chains within the community. In this context, the quality of different face masks is frequently discussed and should, therefore, be evaluated. In this study, nanofleece textiles with a particle filtering effect and textiles with a self-disinfecting treatment were examined, which may be combined in face masks. Firstly, newly developed nanofleece textiles were tested regarding their filtration efficiency against airborne coronavirus, using feline coronavirus (FCoV) as a surrogate for SARS-CoV-2. The tested nanofleece textiles showed filtration efficiencies of over 95% against FCoV when used as a double layer and were, therefore, almost on par with the FFP-2 mask material, which was used as a reference. Secondly, eight treated, self-disinfecting textiles, which may increase the safety in the handling of potentially contaminated masks, were tested against SARS-CoV-2. Three out of eight treated textiles showed significant activity against SARS-CoV-2 and achieved about three LOG10 (99.9%) of virus titer reduction after twelve hours of incubation. Since all possible transmission paths of SARS-CoV-2, as well as the minimal infection doses, remain unknown, both investigated approaches seem to be useful tools to lower the virus spread within the community.
| S-EPMC8402066 | biostudies-literature
Project description:BackgroundIt is uncertain if medical masks offer similar protection against COVID-19 compared with N95 respirators.ObjectiveTo determine whether medical masks are noninferior to N95 respirators to prevent COVID-19 in health care workers providing routine care.DesignMulticenter, randomized, noninferiority trial. (ClinicalTrials.gov: NCT04296643).Setting29 health care facilities in Canada, Israel, Pakistan, and Egypt from 4 May 2020 to 29 March 2022.Participants1009 health care workers who provided direct care to patients with suspected or confirmed COVID-19.InterventionUse of medical masks versus fit-tested N95 respirators for 10 weeks, plus universal masking, which was the policy implemented at each site.MeasurementsThe primary outcome was confirmed COVID-19 on reverse transcriptase polymerase chain reaction (RT-PCR) test.ResultsIn the intention-to-treat analysis, RT-PCR-confirmed COVID-19 occurred in 52 of 497 (10.46%) participants in the medical mask group versus 47 of 507 (9.27%) in the N95 respirator group (hazard ratio [HR], 1.14 [95% CI, 0.77 to 1.69]). An unplanned subgroup analysis by country found that in the medical mask group versus the N95 respirator group RT-PCR-confirmed COVID-19 occurred in 8 of 131 (6.11%) versus 3 of 135 (2.22%) in Canada (HR, 2.83 [CI, 0.75 to 10.72]), 6 of 17 (35.29%) versus 4 of 17 (23.53%) in Israel (HR, 1.54 [CI, 0.43 to 5.49]), 3 of 92 (3.26%) versus 2 of 94 (2.13%) in Pakistan (HR, 1.50 [CI, 0.25 to 8.98]), and 35 of 257 (13.62%) versus 38 of 261 (14.56%) in Egypt (HR, 0.95 [CI, 0.60 to 1.50]). There were 47 (10.8%) adverse events related to the intervention reported in the medical mask group and 59 (13.6%) in the N95 respirator group.LimitationPotential acquisition of SARS-CoV-2 through household and community exposure, heterogeneity between countries, uncertainty in the estimates of effect, differences in self-reported adherence, differences in baseline antibodies, and between-country differences in circulating variants and vaccination.ConclusionAmong health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR-confirmed COVID-19 for medical masks when compared with HRs of RT-PCR-confirmed COVID-19 for N95 respirators. The subgroup results varied by country, and the overall estimates may not be applicable to individual countries because of treatment effect heterogeneity.Primary funding sourceCanadian Institutes of Health Research, World Health Organization, and Juravinski Research Institute.
| S-EPMC9707441 | biostudies-literature
Project description:SARS-CoV-2 spreads by infectious aerosols and droplets from the respiratory tract. Masks and respirators can reduce the transmission of infectious respiratory diseases by collecting these aerosols at the source. The ability of source control devices to block aerosols can be tested by expelling an aerosol through a headform using constant airflows, which are simpler, or cyclic airflows, which are more realistic but require more complex methods. Experiments with respirators found that using cyclic vs. constant flows affected the amount of aerosol inhaled, but similar comparisons have not been made for source control devices with exhaled aerosols. We measured the collection efficiencies for exhaled aerosols for two cloth masks, two medical masks with and without an elastic mask brace, a neck gaiter, and an N95 filtering facepiece respirator using 15 L/min and 85 L/min constant and cyclic flows and a headform with pliable skin. The collection efficiencies for the 15 L/min cyclic flow, 15 L/min constant flow, and 85 L/min constant flow were not significantly different in most cases. The apparent collection efficiencies for the 85 L/min cyclic flow were artificially increased by rebreathing and refiltration of the aerosol from the collection chamber. The collection efficiencies correlated well with the fit factors (ρ > 0.95) but not the filtration efficiencies (ρ < 0.54). Our results suggest that the aerosol collection efficiency measurements of source control devices are comparable when testing the devices using either constant or cyclic airflows and that the potential for aerosol rebreathing must be considered when conducting experiments.
| S-EPMC10194085 | biostudies-literature
Project description: Not available
| S-EPMC4696596 | biostudies-literature