I have no clue which way to tell you to go. I do know masks can hurt anyone with asthma or copd. I also know children should never wear them. But… I went out and found but a few of the masks studies out there for you all. There are many from every country. I still believe in herd immunity and in proper disinfecting to control any virus or bacteria. Proper cleaning will keep you safe even during our worse flu outbreaks. I know this because I do it and taught my children to do it. It meant pre covid, that we were mocked and bullied for wiping down tables, chairs, desks at school, and other items with antibacterial wipes. I believe you can stay healthy without a mask but should wear one if you are sick. I still believe no child should go to school right after vaccination so they won’t infect others. I got those little handouts from the doctor and it stated my child had this disease from vaccination for up to 72 hours. Anyway, here is what I put together.
Discussion
We found that critical care nurses who assisted with suctioning before intubation and intubation of SARS patients were four times more likely to become infected than nurses who did not. Manipulation of a SARS patient’s oxygen mask was also a high-risk factor. Our findings support reports that exposure to respiratory secretions or activities that generate aerosols can result in SARS transmission to healthcare workers (13).
The 11 nurses in our study who did not enter a SARS patient’s room did not become infected. This finding, along with the finding that respiratory care activities pose high risk, implicates either droplet or limited aerosol generation as a means of transmission to healthcare workers. The finding is compatible with the relative high risk (6% per shift worked) of critical care nurses. Our results did not implicate environmental transmission (i.e., contact through gowns) as a major risk factor. These data are in keeping with the report by Scales and colleagues, in which activities associated with droplet or limited aerosol spread were implicated as important sources of transmission (14).
We found a near 80% reduction in risk for infection for nurses who consistently wore masks (either surgical or N95). This finding is similar to that of Seto and colleagues, who found that both surgical masks and N95 masks were protective against SARS among healthcare workers in Hong Kong hospitals (9). When we compared use of N95 to use of surgical masks, the relative SARS risk associated with the N95 mask was half that for the surgical mask; however, because of the small sample size, the result was not statistically significant. Our data suggest that the N95 mask offers more protection than a surgical mask.
This study focused on critical care nurses working at the first SARS hospital outbreak in Toronto. Since use of personal protective equipment was not standardized during the study period, it was possible to assess the effect of personal protective equipment. The use of personal protective equipment was highly variable because the nurses were often unaware that their patients had SARS. Our results highlight the importance of using personal protective equipment when caring for SARS patients. We estimate that if the entire cohort had used masks consistently, SARS risk would have been reduced from 6% to 1.4% per shift.
A limitation of this study is that it is retrospective. Recall bias on the part of the critical care nurses is a possibility. We believe that by verifying the information provided (e.g., patient care activities) using medical records, and using the medical records to cue the interviewed nurses, we minimized recall bias. Any prospective evaluation (e.g., using an observer in ICU) after the initial outbreak would have been limited by uniformity in use of personal protective equipment (i.e., use of N95 masks, gowns, gloves, goggles). We acknowledge that the study cohort was small, and this limits inferences that can be made. Nevertheless, these data support current recommendations for use of N95 masks and for special precautions when performing intubations on SARS patients
Conclusions: Considering our findings, pulse rates of the surgeon’s increase and SpO2 decrease after the first hour. This early change in SpO2 may be either due to the facial mask or the operational stress. Since a very small decrease in saturation at this level, reflects a large decrease in PaO2, our findings may have a clinical value for the health workers and the surgeons.
https://pubmed.ncbi.nlm.nih.gov/18500410/
They also advised healthcare workers who choose to wear cloth masks to “have at least two and cycle them, so that each one can be washed and dried after daily use. Sanitizer spray or UV disinfection boxes can be used to clean them during breaks in a single day.
These are pragmatic, rather than evidence-based suggestions, given the situation.”
A preprint of a rapid systematic review has assessed the current evidence on respiratory illnesses and the use of face masks (mainly surgical paper masks) in community settings.4
The paper, yet to be peer reviewed, included 31 studies, of which 12 were randomised controlled trials.
The researchers reported that “wearing facemasks can be very slightly protective against primary infection from casual community contact, and modestly protective against household infections when both infected and uninfected members wear facemasks.”
However, they said that many of the studies “suffered from poor compliance and controls.”
They concluded, “The evidence is not sufficiently strong to support widespread use of facemasks as a protective measure against covid-19. However, there is enough evidence to support the use of facemasks for short periods of time by particularly vulnerable individuals when in transient higher risk situations.”
https://www.bmj.com/content/369/bmj.m1422
Results The rates of all infection outcomes were highest in the cloth mask arm, with the rate of ILI statistically significantly higher in the cloth mask arm (relative risk (RR)=13.00, 95% CI 1.69 to 100.07) compared with the medical mask arm. Cloth masks also had significantly higher rates of ILI compared with the control arm. An analysis by mask use showed ILI (RR=6.64, 95% CI 1.45 to 28.65) and laboratory-confirmed virus (RR=1.72, 95% CI 1.01 to 2.94) were significantly higher in the cloth masks group compared with the medical masks group. Penetration of cloth masks by particles was almost 97% and medical masks 44%.
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.
https://bmjopen.bmj.com/content/5/4/e006577
Results
The median-fit factor of the homemade masks was one-half that of the surgical masks. Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask.
Conclusion
Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection. (Disaster Med Public Health Preparedness. 2013;0:1–6
Nevertheless, mechanistic studies found that surgical masks could prevent transmission of human coronavirus and influenza virus infections if worn by infected persons
https://wwwnc.cdc.gov/eid/article/26/8/20-1498_article
Masks do not filter all particulates from the air inhaled and exhaled by the wearer. Much of the air is drawn in and escapes where there is least resistance to flow, usually around the sides of the mask (venting). The masks do not form a complete seal against the face and are therefore not classed as respirators or personal protective equipment (Stull, 1998).
Results
A total of 158 healthcare workers participated in the study. Majority [126/158 (77.8%)] were aged 21‐35 years. Participants included nurses [102/158 (64.6%)], doctors [51/158 (32.3%)], and paramedical staff [5/158 (3.2%)]. Pre‐existing primary headache diagnosis was present in about a third [46/158 (29.1%)] of respondents. Those based at the emergency department had higher average daily duration of combined PPE exposure compared to those working in isolation wards [7.0 (SD 2.2) vs 5.2 (SD 2.4) hours, P < .0001] or medical ICU [7.0 (SD 2.2) vs 2.2 (SD 0.41) hours, P < .0001]. Out of 158 respondents, 128 (81.0%) respondents developed de novo PPE‐associated headaches. A pre‐existing primary headache diagnosis (OR = 4.20, 95% CI 1.48‐15.40; P = .030) and combined PPE usage for >4 hours per day (OR 3.91, 95% CI 1.35‐11.31; P = .012) were independently associated with de novo PPE‐associated headaches. Since COVID‐19 outbreak, 42/46 (91.3%) of respondents with pre‐existing headache diagnosis either “agreed” or “strongly agreed” that the increased PPE usage had affected the control of their background headaches, which affected their level of work performance.
Conclusion
Most healthcare workers develop de novo PPE‐associated headaches or exacerbation of their pre‐existing headache disorders
https://headachejournal.onlinelibrary.wiley.com/doi/full/10.1111/head.13811
Our study demonstrates, for the first time, that pregnant women in mid-pregnancy are unable to maintain their minute ventilation while breathing through N95-mask materials
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647822/
The only negative physiologic change resulting from long-term respiratory protection use was elevated CO2 levels
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7132714/
At 2 metabolic equivalents (e.g., walking slowly during rounds), N95 mask use noticeably increases inhaled carbon dioxide, reduces inspired oxygen, and increases the work of breathing. The resulting inhaled carbon dioxide of 2 to 3% (normal, 0.04%) produces transient acidosis and compensatory increases in minute ventilation, work of breathing, and cardiac output.2 Symptoms include sweating, visual changes, headache, dyspnea, increased irritability, and decreased reasoning, alertness, and exercise endurance.3 Independently, the inspired oxygen of 17% (normal, 21%), yields headache, lightheadedness, drowsiness, muscular weakness, dyspnea on exertion, nausea, and vomiting.4 Simultaneously, the augmented resistance to inspiratory (15% of maximum) and expiratory flow, when experienced for greater than 10 min, results in respiratory alkalosis, increased lactate levels, fatigue, and impaired physical work capacity.5
However, a number of exercise benefits can be achieved with surprisingly low effort while wearing an N95 mask
https://anesthesiology.pubs.asahq.org/article.aspx?articleid=2766085
The widespread use of cloth masks by healthcare workers may actually put them at increased risk of respiratory illness and viral infections and their global use should be discouraged, according to a UNSW study.
https://www.sciencedaily.com/releases/2015/04/150422121724.htm
And finally, I will leave you it’s this!
Could widespread (and proper) use of masks have made a difference where the virus escaped containment? A 2018 studyby Jin Yan and colleagues from the US Food and Drug Administration constructed a model based on assumptions from laboratory data. They concluded that if only 20 percent of people use masks, it wouldn’t make a difference for the spread of influenza. At 50 percent compliance, though, with the use of high-filtration surgical masks, the effect might be substantial. That’s just a theoretical result, and we know that Covid-19 outbreaks have been contained in places without widespread use of masks. On the other hand, when an outbreak is out of control, even a small contribution matters
https://www.wired.com/story/the-face-mask-debate-reveals-a-scientific-double-standard/
Stay safe and protected! My prayers are with us all!
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