https://covidinfos.net/wp-content/uploads/2020/05/...An extensive literature review by a Canadian researcher Denis Rancourt found that face masks do not provide measurable protection against colds and influenza.
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https://pubmed.ncbi.nlm.nih.gov/25903751/Conclusions: This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated.
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https://www.technocracy.news/blaylock-face-masks-p...As for the scientific support for the use of face mask, a recent careful examination of the literature, in which 17 of the best studies were analyzed, concluded that, “ None of the studies established a conclusive relationship between mask/respirator use and protection against influenza infection.” Keep in mind, no studies have been done to demonstrate that either a cloth mask or the N95 mask has any effect on transmission of the COVID-19 virus. Any recommendations, therefore, have to be based on studies of influenza virus transmission. Russell Blaylock, MD Several studies have indeed found significant problems with wearing such a mask. This can vary from headaches, to increased airway resistance, carbon dioxide accumulation, to hypoxia, all the way to serious life-threatening complications.
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https://www.nejm.org/doi/full/10.1056/NEJMp2006372..."We know that wearing a mask outside health care facilities offers little, if any, protection from infection." "In many cases, the desire for widespread masking is a reflexive reaction to anxiety over the pandemic."
"A mask will not protect providers caring for a patient with active Covid-19 if it’s not accompanied by meticulous hand hygiene, eye protection, gloves, and a gown. " "It is also clear that masks serve symbolic roles. Masks are not only tools, they are also talismans that may help increase health care workers’ perceived sense of safety, well-being, and trust in their hospitals. " "Although such reactions may not be strictly logical, we are all subject to fear and anxiety, especially during times of crisis. One might argue that fear and anxiety are better countered with data and education than with a marginally beneficial mask"
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https://www.cadth.ca/use-surgical-masks-operating-...Key Messages ● No evidence was found to support the use of surgical face masks to reduce the frequency of surgical site infections. ● No evidence was found on the effectiveness of wearing surgical face masks to protect staff from infectious material in the operating room. ● Guidelines recommend the use of surgical face masks by staff in the operating room to protect both operating room staff and patients (despite the lack of evidence).
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC44805...However, overall there is a lack of substantial evidence to support claims that facemasks protect either patient or surgeon from infectious contamination. More rigorous contemporary research is needed to make a definitive comment on the effectiveness of surgical facemasks.
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https://onlinelibrary.wiley.com/doi/epdf/10.1111/j...Discussion: None of the studies we reviewed established a conclusive relationship between mask ⁄ respirator use and protection against influenza infection.
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https://pubmed.ncbi.nlm.nih.gov/19216002/Results: Thirty-two health care workers completed the study, resulting in 2464 subject days. There were 2 colds during this time period, 1 in each group. Of the 8 symptoms recorded daily, subjects in the mask group were significantly more likely to experience headache during the study period (P < .05). Subjects living with children were more likely to have high cold severity scores over the course of the study. Conclusion: Face mask use in health care workers has not been demonstrated to provide benefit in terms of cold symptoms or getting colds. A larger study is needed to definitively establish noninferiority of no mask use.
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https://onlinelibrary.wiley.com/doi/epdf/10.1111/j...Conclusion: The use of N95 respirators compared with surgical masks is not associated with a lower risk of laboratory-confirmed influenza. It suggests that N95 respirators should not be recommended for general public and non high-risk medical staff those are not in close contact with influenza patients or suspected patients.
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https://jamanetwork.com/journals/jama/fullarticle/...Face masks should not be worn by healthy individuals to protect themselves from acquiring respiratory infection because there is no evidence to suggest that face masks worn by healthy individuals are effective in preventing people from becoming ill. Face masks should be reserved for those who need them because masks can be in short supply during periods of widespread respiratory infection. Because N95 respirators require special fit testing, they are not recommended for use by the general public.
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https://www.nejm.org/doi/10.1056/NEJMp2006372We know that wearing a mask outside health care facilities offers little, if any, protection from infection. Public health authorities define a significant exposure to Covid-19 as face-to-face contact within 6 feet with a patient with symptomatic Covid-19 that is sustained for at least a few minutes (and some say more than 10 minutes or even 30 minutes). The chance of catching Covid-19 from a passing interaction in a public space is therefore minimal. In many cases, the desire for widespread masking is a reflexive reaction to anxiety over the pandemic. It is also clear that masks serve symbolic roles. Masks are not only tools, they are also talismans that may help increase health care workers’ perceived sense of safety, well-being, and trust in their hospitals. Although such reactions may not be strictly logical, we are all subject to fear and anxiety, especially during times of crisis. One might argue that fear and anxiety are better countered with data and education than with a marginally beneficial mask, particularly in light of the worldwide mask shortage, but it is difficult to get clinicians to hear this message in the heat of the current crisis.
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https://www.cmaj.ca/content/188/8/567In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection
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https://www.acpjournals.org/doi/10.7326/m20-1342We do not know whether masks shorten the travel distance of droplets during coughing. Further study is needed to recommend whether face masks decrease transmission of virus from asymptomatic individuals or those with suspected COVID-19 who are not coughing. In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.
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https://pubmed.ncbi.nlm.nih.gov/25336079/A total of 22 tents were randomised to 'mask' (n=12) or 'control' (n=10). There were 164 pilgrims recruited; 75 in 'mask' and 89 in 'control' group. Mask use compliance was 76% in the 'mask' group and 12% in the 'control' group. Based on developing syndromic ILI, less contacts became symptomatic in the 'mask' tents compared to the 'control' tents (31% versus 53%, p= 0.04). However, laboratory results did not show any difference between the two groups.
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https://pubmed.ncbi.nlm.nih.gov/312/This study showed that the filtering efficiency of cloth face masks were relatively lower, and washing and drying practices deteriorated the efficiency. We believe that the findings of this study will be very helpful for increasing public awareness and help governmental agencies to make proper guidelines and policies for use of face mask.
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https://www.cdc.gov/niosh/nioshtic-2/20033859.html...CONCLUSION: None of these surgical masks exhibited adequate filter performance and facial fit characteristics to be considered respiratory protection devices.
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https://pubmed.ncbi.nlm.nih.gov/20088690/Results: We observed significant reductions in ILI during weeks 4-6 in the mask and hand hygiene group, compared with the control group, ranging from 35% (confidence interval [CI], 9%-53%) to 51% (CI, 13%-73%), after adjusting for vaccination and other covariates. Face mask use alone showed a similar reduction in ILI compared with the control group, but adjusted estimates were not statistically significant. Neither face mask use and hand hygiene nor face mask use alone was associated with a significant reduction in the rate of ILI cumulatively.
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https://www.sciencedaily.com/releases/2015/04/1504...Respiratory infection is much higher among healthcare workers wearing cloth masks compared to medical masks, research shows. Cloth masks should not be used by workers in any healthcare setting. The penetration of cloth masks by particles was almost 97% compared to medical masks with 44%.
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https://pubmed.ncbi.nlm.nih.gov/21103330/Households were randomized either to the mask or control group for 7 days “Influenza-like illness was reported in 24/148 (16.2%) of the contacts in the intervention arm and in 25/158 (15.8%) of the contacts in the control arm.”
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https://wwwnc.cdc.gov/eid/article/26/5/19-0994_art...Here, we review the evidence base on the effectiveness of nonpharmaceutical personal protective measures and environmental hygiene measures in nonhealthcare settings and discuss their potential inclusion in pandemic plans. Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza.
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https://pubmed.ncbi.nlm.nih.gov/22188875/Eight of nine retrospective observational studies found that mask and/or respirator use was independently associated with a reduced risk of severe acute respiratory syndrome (SARS). Findings, however, may not be applicable to influenza and many studies were suboptimal. None of the studies established a conclusive relationship between mask/respirator use and protection against influenza infection. Some evidence suggests that mask use is best undertaken as part of a package of personal protection especially hand hygiene.
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https://pubmed.ncbi.nlm.nih.gov/27531371/Standard N95 mask performance was used as a control to compare the results with cloth masks, and our results suggest that cloth masks are only marginally beneficial in protecting individuals from particles <2.5 μm. Compared with cloth masks, disposable surgical masks are more effective in reducing particulate exposure.
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC48686...In the 1919 influenza pandemic, masks were available and were dispensed to populations, but they had no impact on the epidemic curve. A number of studies have shown the inefficacy of the surgical mask in household settings to prevent transmission of the influenza virus.
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https://pubmed.ncbi.nlm.nih.gov/19193267/We concluded that household use of face masks is associated with low adherence and is ineffective for controlling seasonal respiratory disease.
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https://pubmed.ncbi.nlm.nih.gov/19652172/Results: Sixty (8%) contacts in the 259 households had RT-PCR-confirmed influenza virus infection in the 7 days after intervention. Hand hygiene with or without facemasks seemed to reduce influenza transmission, but the differences compared with the control group were not significant.
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https://pubmed.ncbi.nlm.nih.gov/26952529/ Results: We identified 6 clinical studies (3 RCTs, 1 cohort study and 2 case-control studies) and 23 surrogate exposure studies. In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection.
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https://pubmed.ncbi.nlm.nih.gov/31479137/Conclusions: Among outpatient health care personnel, N95 respirators vs medical masks as worn by participants in this trial resulted in no significant difference in the incidence of laboratory-confirmed influenza.
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https://bmjopen.bmj.com/content/5/4/e006577#T1The rates of CRI, ILI and laboratory-confirmed virus infections were lowest in the medical mask arm, followed by the control arm, and highest in the cloth mask arm. The control arm was ‘standard practice’, which comprised mask use in a high proportion of participants. As such (without a no-mask control), the finding of a much higher rate of infection in the cloth mask arm could be interpreted as harm caused by cloth masks, efficacy of medical masks, or most likely a combination of both.
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https://pubmed.ncbi.nlm.nih.gov/28039289/Results: In an intention-to-treat analysis, rates of clinical respiratory illness, influenza-like illness and laboratory-confirmed viral infections were consistently lower in the mask arm compared with control, although not statistically significant. A post hoc comparison between the mask versus no-mask groups showed a protective effect against clinical respiratory illness, but not against influenza-like illness and laboratory-confirmed viral respiratory infections.