Wearing Face Masks - theory or reality ?

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Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

The American Lung Association say to wear masks to stop the spread of COVID-19; Here’s why


https://www.news-medical.net/news/20201 ... s-why.aspx

What provoked your research into COVID-19 and the use of masks?

There has been some debate over the months since the pandemic started as to the modes of transmission of the COVID-19 virus. Surfaces or fomites are possibly less important than we originally thought, the virus can still be found for different lengths of times on surfaces, depending on the type of surface and surrounding temperature, but it seems that infectivity by the virus is felt to be low and is likely to fade quickly with time.

The mask recommendations have been derived from the fact that the airborne nature of the spread is more apparent now, especially when we realized that these droplets or aerosols were being spewed out by individuals who were minimally symptomatic or not symptomatic at all, but had the infection.

Masks have been recommended at the beginning to protect others from these droplets and aerosols that were generated by the wearer, but now there is also growing evidence that masks may actually help prevent the wearer from getting exposed to the infection also, and may actually decrease the inoculum or the amount of virus that might be inhaled, therefore leading to a less severe infection.

Droplets themselves are usually considered to be 10 to 15 microns in diameter and are generated by people when they cough or sneeze. They usually fall to the ground quickly and account for the six-foot social distancing measure that has been recommended all along.

More importantly, aerosols, which are smaller than droplets (10 to 15 microns), are generated by just talking, breathing, smoking, singing, exercising, and yelling. These particles tend not to fall to the ground very rapidly remaining suspended in the air for hours depending on the surrounding ventilation. That is why outdoor gatherings carry a lower risk of spread. This mode of transmission has been often quoted as the reason for some of the super spreading outbreaks that occur at functions such as weddings, parties, and sporting events.

We actually developed a research protocol for COVID-19, not specifically for masks, but we know masks are being looked at by the researchers who apply to us for funding.

What is the importance of wearing masks in helping to control the spread of COVID-19?

Everyone should wear masks to decrease the spread of COVID-19 from infected and/or asymptomatic wearers and help protect the wearer from inhalation of infectious droplets from others.

Masks are playing a much bigger role in bringing the pandemic under control than was initially thought.

Can you describe the correct way to wear a mask?

Masks are going to work best if they cover the nose and the mouth. When we breathe, talk or sneeze, these droplets come out of both the nose and the mouth, so covering them both helps prevent exposure to others from your droplets.

The same thing helps to protect you. If you inhale through the nose or the mouth, if it is not covered by the mask, it is not going to be able to protect you as well. So, there is definitely places where people, because they feel more comfortable, will not cover the nose, and they will just cover the mouth. We recommend covering both.

The other important thing is to try to have it fit snugly to the face, especially across the bridge of the nose. Many of these masks have a little more stiffness or sometimes even a metal bar over the bridge to fit the mask more securely. But many patients have to balance the snug fit with the comfort of breathing through a mask, and this mainly goes to a lot of the patients I see who already have underlying chronic diseases.

These individuals can manage okay for 10-15 minutes at a time, but the longer they have to be in a mask, they do feel like their breathing's getting too labored. So, they have to take a break, go away from areas where they have to wear the mask for long periods of time, but covering the nose and mouth is particularly important.

What other safety protocols should people follow to limit the spread of COVID-19?

We certainly do not want to forget about the importance of frequent handwashing with soap and water, or at least using alcohol sanitizers with at least 60% solution. Wearing a mask we have already talked about, especially when outside of your home, and practicing the social distancing measures as much as possible. Avoid being around sick individuals as much as possible and try not to go into workplaces if you feel ill because you may actually expose others.

Another recommendation is to simply avoid crowds, especially indoors where we know ventilation may not be optimal, especially for long periods of time. We want to make sure you avoid places where mask-wearing is not being practiced by everybody.

Really be aware of your surroundings and institute all those measures of handwashing, social distancing, and mask-wearing.

How will the upcoming winter months affect the severity of COVID-19, and what could people do to reduce their chances of spreading this virus?

The colder months will likely drive activities that were being able to be handled outdoors indoors, where there is less optimal ventilation, and this will be an issue concerning an increase in spread. The same recommendations apply here as mentioned before, but we also know the winter months do carry with them certain holidays that are certainly covered here in the United States and worldwide.

That unfortunately is going to draw individuals to, who probably missed many family members for months, maybe let their guard down and congregate in homes where there are more people than there should be there, where social distancing cannot take place, and where the ventilation may not be optimal. I think we all realize that these winter months may very well be a worsening of the already present surge that is occurring across the world.

In your latest statement, you have encouraged everyone above 6 months old to get the flu vaccine. Why is this?

In the United States, it has been recommended for a period of time now that the Center for Disease Control feels that immunization best practices includes anyone over the age of six months getting the vaccine.

The more individuals we immunize against the seasonal flu, the more herd immunity is achieved and outbreaks and hotspots where local epidemics can be prevented. This is especially important this year in view of the coexisting COVID pandemic that may already be stretching the resources of the health care community.

We are also stressing the importance of the flu vaccine for the elderly and those with comorbid diseases because we know they are at more risk of developing complications of the flu.

Do you believe that if everyone correctly followed guidelines, we could potentially reduce the number of people catching COVID-19?

Yes, and I believe this is supported by experience in the past with other infectious diseases and pandemics. Even just this past year with the institution of the social distancing measures in the Southern hemisphere, they saw a drop in the influenza rate.

Influenza, just like COVID, is a disease spread by person to person by airborne transmission, and if we can follow measures like this, it should decrease the spread of the COVID-19 virus.

What are the next steps in your research into masks and COVID-19?

As part of our COVID-19 action initiative launched earlier this spring, we have already funded new COVID researchers in areas of immune response, prevention, risk factors, and therapeutics at a level of $3 million.

We are planning on another round of funding later this year. At the same time, we are using our other mission tools of educating the public and healthcare workers and advocating for state and federal legislation that will help eliminate many of the inequities in the social determinants of health we have noted.

The COVID-19 pandemic has certainly shined a light on the fact that communities of color and those who are socioeconomically deprived are suffering more from this disease, and we need to do whatever we can to pass legislation to help people have access to care across the board.

Where can readers find more information?

Lung Helpline & Quitline: https://www.lung.org/help-support/lung- ... o-quitline
You can connect with us by calling 1-800-LUNGUSA (1-800-586-4872 and press 2), submitting a question or live chat when available.
Buy 2, Give 2 masks: https://www.lung.org/get-involved/ways- ... /buy-masks
COVID-19 resources: https://www.lung.org/blog/2020/03/update-covid-19
COVID-19 Action Initiative https://www.lung.org/lung-health-diseas ... 0pandemics.
Posts: 1519
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

Is mask-wearing effective in preventing SARS-CoV-2 transmission?


https://www.news-medical.net/news/20201 ... ssion.aspx

UK-based researchers from HH Wills Physics Laboratory, University of Bristol, released the findings of their review of the efficacy of the face coverings and masks in preventing transmission of coronavirus disease 2019 (COVID-19) on the preprint server medRxiv*. Their study is titled, “How effective are face coverings in reducing transmission of COVID-19?”


The COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has infected over 65.67 million people around the world, and has killed over 1.51 million people. The pandemic was detected late in 2019 in Wuhan, China, and on the 11th of March 2020 was declared a pandemic by the World Health Organization (WHO).

To date, no drugs are effective against the virus and, until an effective vaccine is available for mass use, the risk of contracting the infection remains. Lack of pharmacological measures to prevent and cure the infection has mandated non-pharmacological measures, such as physical distancing, hand hygiene and one of the most important measures – wearing a face covering or a face mask that covers both the nose and mouth.
Aerosols and masks

The researchers write, “The prevailing view presupposes a binary classification between large and small droplets (also called aerosols), which respectively transmit disease via the droplet and airborne routes.”

Controversy regarding face coverings

Around the world, there has been a lot of controversy around wearing a face cover appropriately. Despite this, wearing masks and avoiding large gatherings remain the main agenda of public health campaigns by all major health bodies worldwide. Masks remain one of the most effective ways to prevent the spread of this airborne infection, write the researchers, and this study was conducted to show the efficacy of wearing face coverings correctly in preventing SARS-CoV-2 infection.

The team looked at the underlying physics that prevents the entry of particles with diameters > 1 micron into the nose and mouth of the wearer. As well as analyzing the efficacy of simple cotton or surgical masks, the study attempted to answer several questions regarding the viral load of airborne exhaled particles and the infectious dose from the infected person to the healthy person.

Type of mask

The team wrote, “Agencies like the Centers For Disease Control and Prevention recommend members of the public wear reusable fabric coverings, whereas disposable surgical masks are more common in East Asian countries such as China.” They note that the wide use of surgical masks will lead to a huge amount of plastic waste, so one of the goals of this study was to compare the efficacy of fabric coverings and surgical masks in preventing the infection. In order to compare the two, mathematical modeling studies were used to assess the relative efficacy.

They added, “We argue that face coverings do not eliminate the risk of secondary transmissions, especially in high-risk settings such as in hospitals or amongst large crowds, but should significantly reduce the risk in most settings.”

Personal air filters

The team says that masks can act as a personal air filter by effectively filtering out particles. The size of the particle it can filter out determines its efficacy. The authors of the study concluded from their study:

Droplets and coarser aerosols ( diameter greater than, or equivalent to, 1 µm) contain a significant amount of the virus. These are easily filtered because they are less mobile. The filtering efficacy for these particles 5 µm in diameter or larger is 100%.
Finer aerosols that are between 0.1 and 1 µm are transported around the fibre by the gas flow. Thus, they cannot be stopped. Filtering efficiency is low (30 to 60%) for these particles.

They add, “Both surgical and cotton masks are thus only partially effective at filtering out sub-micrometre aerosols. However, their efficiency rapidly increases as the size increases beyond a micrometre.”

When more effective masks are considered, N95/KN95/FFP2 masks, for example, the filtering efficiency rises. These have “electret fibres which can sustain considerable electrostatic charge.” This raises their efficiency in filtering 0.1 to 1 µm particles.

Which aerosols contain the virus?

The researchers explained that expiratory particles containing the virus could be determined based on their site of origin. Larger droplets, for example, get deposited in the respiratory tract and smaller droplets emerge from lower in the respiratory tract. Droplets from the larynx and lower respiratory tract are between around 0.1 and 10 µm. Those from the oral cavity are between around 10 to 1000 µm. The larger ones are most likely to contain the majority of the viral microbes, but transmission mainly occurs with the smaller droplets.

The team concluded, “For the moderately large viral load of 108 ml−1 the majority of viral aerosols extend into the micron regime greater than, or equivalent to, >1 µm. Only for extremely large viral loads of 1010 ml−1 do the submicron droplets begin to contain significant numbers of virus.”

Can masks prevent community transmission of the infection?

This study shows that masks remove the majority of viral aerosols except for the submicron size particles. These masks are also “more effective with decreasing viral loads”.

Conclusions and implications

The team explains that both masks made from simple cotton fabrics and surgical masks can reduce the risk of transmission of respiratory viruses. Cloth masks provide the advantage of being washable and reusable. They are, therefore, preferable to disposable surgical masks because they generate less plastic waste. However, the fit of cloth masks is generally poorer and more studies are needed to see if they can prevent the transmission of all respiratory viruses, the researchers wrote. “Transmission of respiratory viruses is complex and poorly understood,” they explained.

Some COVID-19 patients have viral loads thousands or millions of times higher than others. Thus, if there is a 50% reduction in viral load dose due to mask-wearing, the risk of infection in the non-infected person may vary. They write, “As typically the viral load of an infectious person will not be known, other forms of interventions may be warranted in addition to masking.”

They concluded that the finest aerosols (< 1 micron) are unlikely to contain the virus and they suggest that masks are “effective at reducing the risk of airborne transmission in most settings.”

Thus, masks are highly effective at reducing transmission rates from the vast majority of people infected with SARS-CoV-2, the team writes.

*Important Notice

medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.

Journal reference:

Joshua F. Robinson, Ioatzin Rios de Anda, Fergus J. Moore, Florence K. A. Gregson, View Jonathan P. Reid, Lewis Husain, Richard P. Sear, C. Patrick Royall. (2020) How effective are face coverings in reducing transmission of COVID-19? medRxiv preprint server. doi: https://doi.org/10.1101/2020.12.01.2024 ... 20241992v1
Posts: 1519
Joined: Fri Jun 26, 2020 5:22 am

Re: Wearing Face Masks - theory or reality ?

Post by trader32176 »

How effective are masks in preventing SARS-CoV-2 transmission?


https://www.news-medical.net/news/20210 ... ssion.aspx

Can face masks protect against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection? Faruque Ahmad, MD, recently explored the role of face masks in mitigating the coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, and potential alternatives that might mitigate its spread. In doing so they highlight some of the complications of universal masking and suggest other practices that might also help curb SARS-CoV-2 transmission. The researcher published their study in the latest issue of Saudi Pharmaceutical Journal (2020).

SARS-CoV-2 is believed to commonly spread through respiratory droplets when an infected individual comes into contact with an uninfected individual. Among the mitigation strategies employed in many countries, then, it has been highly recommended, if not mandatory, that individuals wear face masks when out in public and when interacting with individuals outside of their households. Face masks have thus been integrated into public health policy guidelines to minimize the virus's transmission in many parts of the world.

Because presymptomatic carriers are thought to be responsible for 50% of SARS-CoV-2 infection, a marginal decrease in community transmission with masks might make a big difference. This is despite the fact that “strategic measures of face masks exhibit a false sense of security and may lead to death in specific groups of the people,” suggests Ahmad.

However, under certain circumstances, the researcher suggests that wearing a face mask may provide a false sense of safety and lead to a decline in social distancing and handwashing compliances. Moreover, being a new common practice for most, the level of mask safety may also not be achieved by all and lead to non-compliance in its use, reuse and disposal, potentially increasing the chances of transmission.

Furthermore, in the case of certain conditions such as chronic obstructive pulmonary disease (COPD), acute and chronic respiratory infection, asthma, apnea and dyspnea, etc. it is also advisable to avoid face masks and maintain social distancing and other recommended measures. Restrictive respiration due to a face mask may change the concentration of carbon dioxide in the blood, leading to further complications in this sensitive group. Likewise, during exercise, wearing a face mask is inadvisable.

The present United States Health care Infection Control Practices Advisory Committee (HICPAC) guidelines recommend wearing face shields during the handling of patients, particularly for SARS-CoV-2 and avian influenza. Studies show the benefits of viral protection in face shields (96%) and physical distancing (92%).

Greater protection, repeated use, easy to clean: these are the major advantages of using a face shield, without any of the irritation or discomfort that a face mask may cause, suggests Ahmad. While face shields are enormously useful, social distancing – the age-old, time-tested method – remains the most effective in controlling the spread and preventing fomites infection.

As many countries are facing a second wave of the pandemic surge, the author calls for searching alternates to the face mask.

Overall, the researcher emphasizes that the face shields and social distancing could be better substitutes for face masks for certain groups of people and/or in certain contexts (COPD, acute and chronic respiratory disease, outdoor exercise, old age, underlying medical conditions, and hypercapnia sensitive groups). However, further clinical studies are required to be carried out, the author cautions.

The Centers for Disease Control and Prevention (CDC) currently recommends that: "Everybody should use a cloth face cover in a public place but it should be avoided to be applied on children who are below 2 years or someone who has breathing difficulties, incapacitated or incapable to remove face mask without others assistance.”

While other alternatives may help, as this recent study shows, wearing masks in public remains a crucial preventative measure to mitigate SARS-CoV-2 transmission. The study also highlights the public health risks associated with mask-wearing-based complacency with other crucial mitigatory measures, such as social distancing and hand hygiene.

Journal reference:

Faruque Ahmad, M., A Novel Perspective Approach to Explore Pros and Cons of Face Mask in Prevention the Spread of SARS-CoV-2 and other pathogens, Saudi Pharmaceutical Journal (2020), doi: https://doi.org/10.1016/j.jsps.2020.12.014, https://www.sciencedirect.com/science/a ... via%3Dihub
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