Wearing Face Masks - theory or reality ?

This forum is to discuss general things concerning TSOI.
trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Wearing Face Masks - theory or reality ?

Post by trader32176 »

Wearing Face Masks - theory or reality ?

Background :

trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Hypoxia & Wearing Face Masks

Post by trader32176 »

Anti-Maskers and the face mask debate | COVID-19 Special

trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Effects of Prolonged Use of Facemask on Healthcare Workers in Tertiary Care Hospital During COVID-19 Pandemic


https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7490318/

Conclusion


In conclusion, the use of facemask plays a pivotal role in causing significant discomfort in all the participants during its prolonged usage which can limit the efficient usage of facemask, leading to decreased protection. Since facemasks are essential to protect us from COVID-19, certain strategies can be followed to reduce the heat burden due to its prolonged usage such as encouraging nasal breathing, pre-use refrigeration of the respirator
trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

What Happens To Your Lungs When You Wear A Face Mask Every Day?

trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Episode 58: Can Masks cause Hypoxia?

trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Hypoxia during air travel in adults with pulmonary disease

https://pubmed.ncbi.nlm.nih.gov/18195588/


Abstract

At the present time, commercial aircraft cabins are required to be pressurized to the equivalent of 8,000 feet or less. Although in-flight medical emergencies are infrequent, some adults with pulmonary disease may experience significant physiological stress, exacerbation of their underlying illness, and severe hypoxemia during air travel. A careful preflight medical evaluation is essential to determine which patients with pulmonary disease can fly safely, which patients require supplemental oxygen, and which patients should not fly at all. All adults with pulmonary disease who have a preflight arterial oxygen tension of less than 70 mm Hg or a preflight pulse oximetry saturation of less than 92% should receive supplemental oxygen during air travel. The hypoxia altitude simulation test and the 6-minute walk test are useful when additional evaluation for supplemental in-flight oxygen is needed. Patients with an unstable condition, an acute exacerbation of their pulmonary disease, severe pulmonary hypertension (Class III and Class IV), or an active pneumothorax should not fly.
trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Mask wearing, social distancing considerably reduce incidence of many diseases

11/10/20


https://www.news-medical.net/news/20201 ... ID-19.aspx


Measures to reduce the spread of COVID-19 through non-pharmaceutical interventions (NPIs) such as mask wearing and social distancing are a key tool in combatting the impact of the ongoing coronavirus pandemic.

These actions also have greatly reduced incidence of many other diseases, including influenza and respiratory syncytial virus (RSV).

Current reductions in these common respiratory infections, however, may merely postpone the incidence of future outbreaks, according to a study by Princeton University researchers published Nov. 9 in the Proceedings of the National Academy of Sciences.

"Declines in case numbers of several respiratory pathogens have been observed recently in many global locations," said first author Rachel Baker, an associate research scholar at the High Meadows Environmental Institute (HMEI) at Princeton University.

"While this reduction in cases could be interpreted as a positive side effect of COVID-19 prevention, the reality is much more complex," Baker said. "Our results suggest that susceptibility to these other diseases, such as RSV and flu, could increase while NPIs are in place, resulting in large outbreaks when they begin circulating again."

Baker and her co-authors found that NPIs could lead to a future uptick in RSV -- an endemic viral infection in the United States and a leading cause of lower respiratory-tract infections in young infants -- but that the same effect was not as pronounced for influenza.

" Although the detailed trajectory of both RSV and influenza in the coming years will be complex, there are clear and overarching trends that emerge when one focuses on some essential effects of NPIs and seasonality on disease dynamics."

- Gabriel Vecchi, Study Co-Author and professor, Geosciences, High Meadows Environmental Institute, Princeton University

The researchers used an epidemiological model based on historic RSV data and observations of the recent decline in RSV cases to examine the possible impact of COVID-19 NPIs on future RSV outbreaks in the United States and Mexico.

They found that even relatively short periods of NPI measures could lead to large future RSV outbreaks. These outbreaks were often delayed following the end of the NPI period, with peak cases projected to occur in many locations in winter 2021-22.

"It is very important to prepare for this possible future outbreak risk and to pay attention to the full gamut of infections impacted by COVID-19 NPIs," Baker said.

The authors also considered the implications of COVID-19 NPIs for seasonal influenza outbreaks and found results qualitatively similar to RSV. The dynamics of influenza are much harder to project due to viral evolution, however, which drives uncertainty over future circulating strains and the efficacy of available vaccines.

"For influenza, vaccines could make a big difference," Baker said. "In addition, the impact of NPIs on influenza evolution is unclear but potentially very important."

"The decrease in cases of influenza and RSV -- as well as the possible future increase we project -- is arguably the broadest global impact of NPIs across a variety of human diseases that we've seen," said co-author Bryan Grenfell, the Kathryn Briger and Sarah Fenton Professor of Ecology and Evolutionary Biology and Public Affairs, who is associated faculty in HMEI.

"NPIs could have unintended longer-term impacts on the dynamics of other diseases that are similar to the impact on susceptibility we projected for RSV," he said.

A similar effect of pandemic-related NPIs on other pathogens was observed following the 1918 influenza pandemic. Historic measles data from London show a shift from annual cycles to biennial outbreaks following a period of control measures implemented at that time.

Co-author C. Jessica Metcalf, associate professor of ecology and evolutionary biology and public affairs and an associated faculty member in HMEI, said that directly evaluating the associated risks of NPIs by developing and deploying tools such as serology that would better measure susceptibility is an important public health and policy direction.

"The future repercussions of NPIs revealed by this paper hinge on how these measures change the landscape of immunity and susceptibility," Metcalf said.
trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers

A Randomized Controlled Trial

11/18/20


https://www.acpjournals.org/doi/10.7326/M20-6817


Abstract

Background:


Observational evidence suggests that mask wearing mitigates transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is uncertain if this observed association arises through protection of uninfected wearers (protective effect), via reduced transmission from infected mask wearers (source control), or both.

Objective:

To assess whether recommending surgical mask use outside the home reduces wearers' risk for SARS-CoV-2 infection in a setting where masks were uncommon and not among recommended public health measures.

Design:

Randomized controlled trial (DANMASK-19 [Danish Study to Assess Face Masks for the Protection Against COVID-19 Infection]). (ClinicalTrials.gov: NCT04337541)

Setting:

Denmark, April and May 2020.

Participants:

Adults spending more than 3 hours per day outside the home without occupational mask use.

Intervention:

Encouragement to follow social distancing measures for coronavirus disease 2019, plus either no mask recommendation or a recommendation to wear a mask when outside the home among other persons together with a supply of 50 surgical masks and instructions for proper use.

Measurements:

The primary outcome was SARS-CoV-2 infection in the mask wearer at 1 month by antibody testing, polymerase chain reaction (PCR), or hospital diagnosis. The secondary outcome was PCR positivity for other respiratory viruses.

Results:

A total of 3030 participants were randomly assigned to the recommendation to wear masks, and 2994 were assigned to control; 4862 completed the study. Infection with SARS-CoV-2 occurred in 42 participants recommended masks (1.8%) and 53 control participants (2.1%). The between-group difference was −0.3 percentage point (95% CI, −1.2 to 0.4 percentage point; P = 0.38) (odds ratio, 0.82 [CI, 0.54 to 1.23]; P = 0.33). Multiple imputation accounting for loss to follow-up yielded similar results. Although the difference observed was not statistically significant, the 95% CIs are compatible with a 46% reduction to a 23% increase in infection.

Limitation:

Inconclusive results, missing data, variable adherence, patient-reported findings on home tests, no blinding, and no assessment of whether masks could decrease disease transmission from mask wearers to others.

Conclusion:

The recommendation to wear surgical masks to supplement other public health measures did not reduce the SARS-CoV-2 infection rate among wearers by more than 50% in a community with modest infection rates, some degree of social distancing, and uncommon general mask use. The data were compatible with lesser degrees of self-protection.
trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Consistent use of face masks slows the spread of COVID-19

11/25/20


https://www.news-medical.net/news/20201 ... ID-19.aspx


The use of face masks to help slow the spread of COVID-19 has been widely recommended by health professionals. This has triggered studies exploring the physics of face mask use and disease transmission, as well as investigations into materials, design, and other issues affecting the way face masks work.

In Physics of Fluids, by AIP Publishing, investigators looked at research on face masks and their use and summarized what we know, to date, about the way face masks filter or block the virus. They also summarize design issues that still need to be addressed.

One key aspect of face mask function involves the size of fluid droplets expelled from the nose and mouth when a person talks, sings, sneezes, coughs, or even simply breathes.

Larger droplets, with sizes around 5-10 microns, are the most common. These droplets are still quite small, however. To compare, a human hair is about 70 microns in diameter.

Even smaller droplets, those below 5 microns, are possibly more dangerous. These can become aerosolized and remain suspended in air for long periods. Among the many types of masks in use (cloth masks, surgical masks, and N95 masks), only N95s can filter out aerosol-sized droplets.

The performance of face masks worn for many hours, such as by health care or other essential workers, impact how effective overall mask wearing can be. Thermal comfort is an important issue, especially in hot and humid environments.

The investigators found face masks made of hybrid polymer materials could filter particles at high efficiency while simultaneously cooling the face. The fibers used in these special masks are transparent to infrared radiation, allowing heat to escape from beneath the mask.

" There could be some relation between breathing resistance and the flow resistance of the face mask which will need to be studied for a face mask-wearing interval. Also, the environmental condition in the compartmental space within the face mask will need to be more accurately quantified using miniaturized sensors and the development of human replicas for such studies."

- Heow Pueh Lee, Study Author, American Institute of Physics

The investigators also reviewed epidemiological studies aimed at discovering whether face masks reduce the effective reproduction number. If the reproduction number drops below 1, the epidemic stops spreading. One study used COVID-19 data from New York state.

"The results suggest that the consistent use of efficient face masks, such as surgical masks, could lead to the eradication of the pandemic if at least 70% of the residents use such masks in public consistently," said author Sanjay Kumar. "Even less efficient cloth masks could also slow the spread if worn consistently."
trader32176
Posts: 2525
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

The curious case of the Danish mask study

11/26/20


https://www.bmj.com/content/371/bmj.m4586


BMJ 2020; 371 doi: https://doi.org/10.1136/bmj.m4586 (Published 26 November 2020) Cite this as: BMJ 2020;371:m4586


DANMASK-19, the first trial of mask use during covid-19, was “negative.” Masks didn’t work. We knew this before the trial was published because we were told so on social media. The authors were reported by the media to be struggling to find a major journal for their trial.1 Journals weren’t proving brave enough to publish the study, said the authors, and they didn’t make a preprint available.

When the mythical trial was finally published last week in the Annals of Internal Medicine we didn’t need to read it. We already knew its damning verdict on mask wearing. Social media told us as much. Eminent professors of evidence based medicine, Carl Heneghan and Tom Jefferson, confirmed this in an article for the Spectator.2

Except that if you read the published paper you find almost the exact opposite.345 The trial is inconclusive rather than negative, and it points to a likely benefit of mask wearing to the wearer—it did not examine the wider potential benefit of reduced spread of infection to others—and this even in a population where mask wearing isn’t mandatory and prevalence of infection is low. This finding is in keeping with summaries of evidence from Cochrane.

A disagreement among experts, especially about interpretation of a study, is a common occurrence. It is the usual business of science. Only, Facebook didn’t see it that way. The social media platform that allows statements about injecting bleach to prevent covid-19, as well as calls to behead the leading US expert on pandemics,67 decreed that Heneghan and Jefferson should be censured for misinformation after they reposted their Spectator article on the site.

It is possible to disagree with Heneghan and Jefferson about the robustness and interpretation of the DANMASK-19 trial—which I do—and still believe it is wrong that their opinion of it was marked as “false information.”8 It seems 2020 is Orwell’s 1984, where the boundaries of public discourse are governed by multibillion dollar corporations (in place of a totalitarian regime) and secret algorithms coded by unidentified employees. Where is Facebook’s accountability for the lies and damaging misinformation910 that it has peddled on controversial topics such as mental health and suicides,11 minorities,12 and vaccines1314?

The problem is less that Facebook and other social media decide what is published on their platforms,15 just as The BMJ’s editors decide what is published on bmj.com. Sacha Baron Cohen and Carole Cadwalladr, among others, have argued that this is exactly what these tech giants should do.1617 It is more that Facebook in particular purports to allow freedom of speech on its platform but acts selectively, seemingly without logic, consistency, or transparency. That is how control of facts and opinions furthers hidden agendas and manipulates the public.

You might expect a national body like Public Health England to offer the best advice on mask wearing, but PHE is no more after seven years of controversy.18 Its proximity to government and industry, together with funding cuts to local authorities, essentially set it up to fail and now to become the government’s fall guy for a flawed pandemic response. PHE is being replaced by a national institute for health protection, which may well be closer still to government and industry. When accountable national organisations move in the direction of political and commercial interests, public trust is eroded, and the power of unaccountable and self-serving social media platforms only grows.
Post Reply