Interesting video on masks

[fsufool]

This is a layup to refute. Most of the virus is carried in water particles. The mask is intended to mitigate the risk. That means to make it less. Put a new mask on and wear it for an hour. The mask at the end will contain more moisture then when you put it on. Therefore if there was virus in the the water you were expelling, some of it would be caught in the mask. That means less virus in the air to infect others. That is a mitigation of the spread of the virus. You do not need studies to figure this out. If you have close contact with an infected individual for a prolonged period of time it probably is useless to expect a mask to protect you, but if you walk by someone in the grocery store who is infected and wearing a mask it just might. Micron size is mostly meaningless because very little of virus is floating around without being encased in water droplets.

Studies have indicated you need prolonged (more than 15 minutes) intimate contact with an infected person, shedding virus to be infected. Casual, walk by, contact isn't going to do it. Outdoor contact isn't going to do it. Most of the spread happens either in homes, institutions or at work. That's why closing the schools worked to mitigate the spread. We have had hundreds of football games with thousands, sometimes over 80,000 folks attending and no outbreaks. Very little traceable outbreaks to grocery stores, whether mask mandated or not, despite never closing them down. Despite this, Delta is very contagious and pretty much guarantees it becomes endemic because most of the population is either going to spend time at work, at school, in a multiple person home, or spend some time in an institution of some sort (hospital, prison, dorm, LTC, etc.) No one is an island...............

Most states have more than 50% of their population having been infected (I live in one that only has 20%). Roughly two thirds of 12 and over have been vaccinated. Recent studies have suggested that the reinfection rate and/or those having been vaccinated is as high as 1%. Fortunately, reinfections are mostly mild or asymptomatic. Soon the CDC will come to its senses and realize that tracking infections isn't doing anything since it is endemic and we can leave this mess behind. More important, is the amount of treatments that have come along for early mild and well as late serious infections. Covid will probably end up like influenza and cause 50K to 200K deaths in any given year almost exclusively to older folks and take its place as another of the many opportunistic infections we have circulating.

 

[chumleynole]

Studies have indicated you need prolonged (more than 15 minutes) intimate contact with an infected person, shedding virus to be infected. Casual, walk by, contact isn't going to do it. Outdoor contact isn't going to do it. Most of the spread happens either in homes, institutions or at work. That's why closing the schools worked to mitigate the spread. We have had hundreds of football games with thousands, sometimes over 80,000 folks attending and no outbreaks. Very little traceable outbreaks to grocery stores, whether mask mandated or not, despite never closing them down. Despite this, Delta is very contagious and pretty much guarantees it becomes endemic because most of the population is either going to spend time at work, at school, in a multiple person home, or spend some time in an institution of some sort (hospital, prison, dorm, LTC, etc.) No one is an island...............

Most states have more than 50% of their population having been infected (I live in one that only has 20%). Roughly two thirds of 12 and over have been vaccinated. Recent studies have suggested that the reinfection rate and/or those having been vaccinated is as high as 1%. Fortunately, reinfections are mostly mild or asymptomatic. Soon the CDC will come to its senses and realize that tracking infections isn't doing anything since it is endemic and we can leave this mess behind. More important, is the amount of treatments that have come along for early mild and well as late serious infections. Covid will probably end up like influenza and cause 50K to 200K deaths in any given year almost exclusively to older folks and take its place as another of the many opportunistic infections we have circulating.

There is a chicken or egg argument here. First off I cannot find the studies with the 15 minute close contact rule. The CDC does use that criteria to define a reportable exposure. If there have not been much in the way of casual or walk by transmission it is possible that that is due to the mitigation efforts that have been put in place.

 

[GbrNole]

Most states have more than 50% of their population having been infected (I live in one that only has 20%).

great notes @fsufool.

with respect to the above, i'm becoming less inclined to believe the accuracy of the CDC's projection as to the number of people that have been infected - the CDC's May 2021 projection was 38%. at this point there should be some alignment between the CDC's projection and the percentage with nucleoprotein found (only occurring in those with natural immunity) when performing seroprevalence tests in blood donors.

seroprevalence percentage of nucleoprotein does exceed the percentage of case load by about 162% (approximately 22% vs approximately 13.6%). there are age limitations to the blood donor test method since it's generally limited to those 16 and older and the younger age groups do have a higher incidence rate of nucleoprotein but even in the youngest tested 16-29 age group it is still under 30%.

the almost identical data is being found in the UK's seroprevalence tests.

COVID Data Tracker

CDC’s home for COVID-19 data. Visualizations, graphs, and data in one easy-to-use website.

covid.cdc.gov

 

[fsufool]

There is a chicken or egg argument here. First off I cannot find the studies with the 15 minute close contact rule. The CDC does use that criteria to define a reportable exposure. If there have not been much in the way of casual or walk by transmission it is possible that that is due to the mitigation efforts that have been put in place.

There is at least a full generation of research on viral spread. That is what is so frustrating for many of us. To ignore all this research was foolish. The original "masks don't help" CDC advise was based on that research. Since then there has been no consensus of research to counter that. The original consensus was 30 minutes of close contact. It was, like a lot of the scientific consensus, made more conservative with the "with an abundance of caution" moniker. The original mitigation was about not overwhelming the hospitals. Looking back that made sense in some areas, but not all. Somewhere along this trip, public health officials and politicians let their egos get out of control and started to think they could stop this respiratory virus from spreading. That was fool's gold as many top epidemiologist suggested early on. Now we pay the price for the mistakes with a damaged economy, higher debt, damaged family finances, mental health issues, higher murder rate, political acrimony, finger pointing, and lack of trust in institutions (can't blame this all on the pandemic as it was already trending). It will be decades before we are clear of the damage done. Unfortunately, I don't see any evidence we are going to handle the next deadly novel virus any better.

 

[GbrNole]

There is a chicken or egg argument here. First off I cannot find the studies with the 15 minute close contact rule. The CDC does use that criteria to define a reportable exposure. If there have not been much in the way of casual or walk by transmission it is possible that that is due to the mitigation efforts that have been put in place.

the distance and time are just a guideline. hospital workers had clearly shown that through December 2020. the WHO for example only requires 3 feet distancing. most of europe 1 meter. some places 5 feet. it's all arbitrary.

the 15 minutes recommendation originated from a Japanese micro-droplet aerosol spread study where it was found that in an unventilated confined space that aerosol spread (cough or sneeze) from a single infected person could cover the entire space of a classroom size room (no specific size given) in just under 20 minutes.

the moment ventilation was added (a window or door opened) the room was cleared in seconds.

 

[fsufool]

great notes @fsufool.

with respect to the above, i'm becoming less inclined to believe the accuracy of the CDC's projection as to the number of people that have been infected - the CDC's May 2021 projection was 38%. at this point there should be some alignment between the CDC's projection and the percentage with nucleoprotein found (only occurring in those with natural immunity) when performing seroprevalence tests in blood donors.

seroprevalence percentage of nucleoprotein does exceed the percentage of case load by about 162% (approximately 22% vs approximately 13.6%). there are age limitations to the blood donor test method since it's generally limited to those 16 and older and the younger age groups do have a higher incidence rate of nucleoprotein but even in the youngest tested 16-29 age group it is still under 30%.

the almost identical data is being found in the UK's seroprevalence tests.

COVID Data Tracker

CDC’s home for COVID-19 data. Visualizations, graphs, and data in one easy-to-use website.

covid.cdc.gov

Interesting......tell me since I don't know...............T cell immunity is above and beyond this right?

 

[fsufool]

great notes @fsufool.

with respect to the above, i'm becoming less inclined to believe the accuracy of the CDC's projection as to the number of people that have been infected - the CDC's May 2021 projection was 38%. at this point there should be some alignment between the CDC's projection and the percentage with nucleoprotein found (only occurring in those with natural immunity) when performing seroprevalence tests in blood donors.

seroprevalence percentage of nucleoprotein does exceed the percentage of case load by about 162% (approximately 22% vs approximately 13.6%). there are age limitations to the blood donor test method since it's generally limited to those 16 and older and the younger age groups do have a higher incidence rate of nucleoprotein but even in the youngest tested 16-29 age group it is still under 30%.

the almost identical data is being found in the UK's seroprevalence tests.

COVID Data Tracker

CDC’s home for COVID-19 data. Visualizations, graphs, and data in one easy-to-use website.

covid.cdc.gov

According to the CDC, the August seroprevalence survey is 89.6%!!!!!

 

[GbrNole]

Interesting......tell me since I don't know...............T cell immunity is above and beyond this right?

yes. T-cells are our seek and destroy cells. it's the T-cell immunity in original SARS infected people that continues to persist some 17 years later.

i saw a 2008 study recently also where scientists tested blood samples collected from very elderly survivors of the 1918 pandemic (young children at the time) and nearly 100 years later their blood samples continued to show effective immune levels to that specific strain of influenza.

Neutralizing antibodies derived from the B cells of 1918 influenza pandemic survivors - Nature

The isolation of neutralizing antibodies to proteins from the 1918 H1N1 influenza virus from the blood of pandemic survivors sets a new yardstick for the persistence of an immune response. The blood samples were collected from 32 survivors aged between 91 and 101 years. They were 2 to 12 years...

www.nature.com

 

[GbrNole]

According to the CDC, the August seroprevalence survey is 89.6%!!!!!

yep that's combined for the spike protein found in both vaccinated people and natural immunity and separately the nucleoprotein found in only naturally immune people.

 

[fsufool]

yep that's combined for the spike protein found in both vaccinated people and natural immunity and separately the nucleoprotein found in only naturally immune people.

You would think that the CDC/media would be trumpeting that number........................instead of the current infection numbers they keep publicizing.

 

[fsufool]

yes. T-cells are our seek and destroy cells. it's the T-cell immunity in original SARS infected people that continues to persist some 17 years later.

i saw a 2008 study recently also where scientists tested blood samples collected from very elderly survivors of the 1918 pandemic (young children at the time) and nearly 100 years later their blood samples continued to show effective immune levels to that specific strain of influenza.

Neutralizing antibodies derived from the B cells of 1918 influenza pandemic survivors - Nature

The isolation of neutralizing antibodies to proteins from the 1918 H1N1 influenza virus from the blood of pandemic survivors sets a new yardstick for the persistence of an immune response. The blood samples were collected from 32 survivors aged between 91 and 101 years. They were 2 to 12 years...

www.nature.com

From the study:

Here we show that of the 32 individuals tested that were born in or before 1915, each showed seroreactivity with the 1918 virus, nearly 90 years after the pandemic. Seven of the eight donor samples tested had circulating B cells that secreted antibodies that bound the 1918 HA.

The antibodies bound to the 1918 HA protein with high affinity, had exceptional virus-neutralizing potency and protected mice from lethal infection.

Interesting and so counter to what the CDC/Media is spewing out now.

 

[F4Gary]

You would think that the CDC/media would be trumpeting that number........................instead of the current infection numbers they keep publicizing.

There is too much money to be made...
😉

 

[chumleynole]

There is at least a full generation of research on viral spread. That is what is so frustrating for many of us. To ignore all this research was foolish. The original "masks don't help" CDC advise was based on that research. Since then there has been no consensus of research to counter that. The original consensus was 30 minutes of close contact. It was, like a lot of the scientific consensus, made more conservative with the "with an abundance of caution" moniker. The original mitigation was about not overwhelming the hospitals. Looking back that made sense in some areas, but not all. Somewhere along this trip, public health officials and politicians let their egos get out of control and started to think they could stop this respiratory virus from spreading. That was fool's gold as many top epidemiologist suggested early on. Now we pay the price for the mistakes with a damaged economy, higher debt, damaged family finances, mental health issues, higher murder rate, political acrimony, finger pointing, and lack of trust in institutions (can't blame this all on the pandemic as it was already trending). It will be decades before we are clear of the damage done. Unfortunately, I don't see any evidence we are going to handle the next deadly novel virus any better.

Are you an epidemiologist? Do you have some scientific background that would make your opinion credible? There are people whose education and fields of expertise make them particularly qualified to form opinions on how to mitigate this virus. They overwhelmingly disagree with you, as does the CDC. I will go with the experts and discounting their opinions based on some perceived bias is not a legitimate argument.

 

[F4Gary]

The CDC has lost all credibility with me. Lord Fauci too.

 

[fsufool]

Are you an epidemiologist? Do you have some scientific background that would make your opinion credible? There are people whose education and fields of expertise make them particularly qualified to form opinions on how to mitigate this virus. They overwhelmingly disagree with you, as does the CDC. I will go with the experts and discounting their opinions based on some perceived bias is not a legitimate argument.

No, but I can understand scientific studies. Can you? I have a PhD is social psychology and took graduate level classes with top level epidemiologist and health care policy professors. You choose to believe who you want. Typical in you don't discuss anything of what I have posted, just try to attack me personally. Your deference to authority is very telling. Critical thinker you are not. You may note that there are folks on here that do work for big pharma and data analysis for hospitals that post similar sentiments and analysis. The most senior epidemiologist at Stanford, Harvard, et al. also have continuously publicly said what I parrot on here.

 

[chumleynole]

No, but I can understand scientific studies. Can you? I have a PhD is social psychology and took graduate level classes with top level epidemiologist and health care policy professors. You choose to believe who you want. Typical in you don't discuss anything of what I have posted, just try to attack me personally. Your deference to authority is very telling. Critical thinker you are not. You may note that there are folks on here that do work for big pharma and data analysis for hospitals that post similar sentiments and analysis. The most senior epidemiologist at Stanford, Harvard, et al. also have continuously publicly said what I parrot on here.

I have debated you on these subjects before. It was useless. In my opinion your education has been overwhelmed by your bias. I am moving on and stand by what I wrote previously.

 

[fsufool]

I have debated you on these subjects before. It was useless. In my opinion your education has been overwhelmed by your bias. I am moving on and stand by what I wrote previously.

Bias???? I have just quoted the science. Commented on the lack of consensus. No bias there..............Show me the bias???? Again, you don't debate if you just say I choose to believe what these folks say and won't bother to look at all the science??????? Many people on here have pointed out where you are posting belief and the science is the opposite.

This is an example of absolute belief that contradicts what all the science says on spread of the virus:

"It is my opinion that mask use is a useful tool in mitigating the virus spread when you are exposed to the virus for a brief period of time, in a relatively well ventilated environment. In other words, if someone were to walk into my office and was several feet away it might prevent an illness if that exposure was brief and we both were masked."

 

[chumleynole]

Bias???? I have just quoted the science. Commented on the lack of consensus. No bias there..............Show me the bias???? Again, you don't debate if you just say I choose to believe what these folks say and won't bother to look at all the science??????? Many people on here have pointed out where you are posting belief and the science is the opposite.

This is an example of absolute belief that contradicts what all the science says on spread of the virus:

"It is my opinion that mask use is a useful tool in mitigating the virus spread when you are exposed to the virus for a brief period of time, in a relatively well ventilated environment. In other words, if someone were to walk into my office and was several feet away it might prevent an illness if that exposure was brief and we both were masked."

This is why I no longer debate you. You make a statement of fact that is only supported by your interpretation of the science. For you to be correct in your statement above you will have to prove that there is no casual transmission of the virus and that if there were masks would not be useful. You will not find that study. That makes your above statement false. Like I said before I will continue to listen to the people who are qualified to have an opinion on the science. I simply do not believe you are an impartial person in regards to this virus and you cherry pick the science that supports your opinion.

 

[chumleynole]

No, but I can understand scientific studies. Can you? I have a PhD is social psychology and took graduate level classes with top level epidemiologist and health care policy professors. You choose to believe who you want. Typical in you don't discuss anything of what I have posted, just try to attack me personally. Your deference to authority is very telling. Critical thinker you are not. You may note that there are folks on here that do work for big pharma and data analysis for hospitals that post similar sentiments and analysis. The most senior epidemiologist at Stanford, Harvard, et al. also have continuously publicly said what I parrot on here.

I have not attacked you. I simply have made an observation based on your posts since the beginning of the pandemic that you are biased. You have taken a view point since the very inception that to me appears based on your personal beliefs. You however have insulted me. I have debated the substance of your posts in the past. I found it very frustrating because you absolutely will not acknowledge anything contrary to what you believe even when it is obvious what you have posted is erroneous.

 

[fsufool]

This is why I no longer debate you. You make a statement of fact that is only supported by your interpretation of the science. For you to be correct in your statement above you will have to prove that there is no casual transmission of the virus and that if there were masks would not be useful. You will not find that study. That makes your above statement false. Like I said before I will continue to listen to the people who are qualified to have an opinion on the science. I simply do not believe you are an impartial person in regards to this virus and you cherry pick the science that supports your opinion.

Again, you fail to respond to what I have said. You need to show me peer reviewed scientific studies that demonstrate casual spread of viral infection from several feet away in a "well ventilated" room after a "brief period of time."

Here is the quote again:

""It is my opinion that mask use is a useful tool in mitigating the virus spread when you are exposed to the virus for a brief period of time, in a relatively well ventilated environment. In other words, if someone were to walk into my office and was several feet away it might prevent an illness if that exposure was brief and we both were masked."

Until you do, then this statement is one of belief not backed up by any scientific evidence. You can tell me I am biased all day long, but a look at the history of my posts on this matter demonstrate regurgitation of scientific studies. For someone you claim is bias; why am I vaccinated (from the first day it was possible for my age group)? Why is my entire family vaccinated?
Your issue is simply that you "believe." Deference to authority is IMO un-American, although most people do it. Obviously you are an intelligent person, but fear has gotten the best of you.

The answer to the question above is there is ample scientific evidence that vaccinations decrease risk of hospitalization and death in all age groups by a significant amount. There is little evidence of risk of injury or death from the vaccination. Simple risk/benefit analysis. Getting vaccinated is a risk reduction behavior. (no matter how small that initial risk is)

Finally, I do not care if you wear a mask during any encounter. I don't care if you wear a mask for the rest of your life. My point is only to have a discussion on here that includes what the science says and what it doesn't. And it doesn't say there is risk of viral spread from a few minutes of casual contact in a well ventilated room from several feet apart when unmasked. It just doesn't. And that is not my bias..............no matter what you claim.

 

[GbrNole]

here's a link to an Israeli study on COVID spread not specific to masks but masks were material to it. the study occurred during an outbreak in a hospital setting, generally some of the most well ventilated structures in any civilized location, the patients were surgical masked and the medical staff was in full PPE.

Eurosurveillance | Nosocomial outbreak caused by the SARS-CoV-2 Delta variant in a highly vaccinated population, Israel, July 2021

A nosocomial outbreak of SARS-CoV-2 Delta variant infected 42 patients, staff and family members; 39 were fully vaccinated. The attack rate was 10.6% (16/151) among exposed staff and reached 23.7% (23/97) among exposed patients in a highly vaccinated population, 16–26 weeks after vaccination...

www.eurosurveillance.org

 

[buckeyenole]

The masks don't stop the flow of oxygen so how do they make it hard to breathe?
Numbers 2-3 are solved by simply changing masks or washing them daily.

I have an 80 year old mother in law. Healthy. Lives in Florida. No physical problems. Has passed out twice due to wearing a surgical mask, and feels dizzy and faint almost every time she wears one. I also know numerous 4-5 year olds that panic after wearing a mask for a few minutes. I know others of the same age that are not affected this way.

Also, in Ohio, kids of all ages who have an IEP are exempt from wearing a mask.

 

[PopsNole]

I have an 80 year old mother in law. Healthy. Lives in Florida. No physical problems. Has passed out twice due to wearing a surgical mask, and feels dizzy and faint almost every time she wears one. I also know numerous 4-5 year olds that panic after wearing a mask for a few minutes. I know others of the same age that are not affected this way.

Also, in Ohio, kids of all ages who have an IEP are exempt from wearing a mask.

Sounds like she’s having a panic attack or mental related stress issue while wearing one as opposed to oxygen not arriving to her lungs.

 

[buckeyenole]

Sounds like she’s having a panic attack or mental related stress issue while wearing one as opposed to oxygen not arriving to her lungs.

Nope. Not that. Calm, cool, and collected. Just suddenly passes out.

There's actually a fair amount of literature out for over a year on the negative affect of masks on the elderly. And small children.

 

[PopsNole]

Nope. Not that. Calm, cool, and collected. Just suddenly passes out.

There's actually a fair amount of literature out for over a year on the negative affect of masks on the elderly. And small children.

There are studies out there on the elderly that have COPD not perfectly healthy once suddenly passing out from masks that I'm aware of. If there are any studies saying that healthy elderly individuals may just suddenly pass out then I'm happy to read it. Also, I'm not sure just blacking out with no prior symptoms makes any sense whatsoever if it's a lack of oxygen issue.

 

[buckeyenole]

There are studies out there on the elderly that have COPD not perfectly healthy once suddenly passing out from masks that I'm aware of. If there are any studies saying that healthy elderly individuals may just suddenly pass out then I'm happy to read it. Also, I'm not sure just blacking out with no prior symptoms makes any sense whatsoever if it's a lack of oxygen issue.

It's a build up of carbon dioxide in the mask, along with somewhat increased difficulty in inhaling in general. I would be surprised if older people have generally lower blood oxygen levels. As you noted, people with COPD have lower blood oxygen levels (though you didn't say that specifically). Also, it's not "suddenly passing out." It's not feeling right, then getting dizzy, and then passing out ('fainting'). Many older people have this symptom progression while wearing masks without getting all the way to passing out.

 

[PopsNole]

It's a build up of carbon dioxide in the mask, along with somewhat increased difficulty in inhaling in general. I would be surprised if older people have generally lower blood oxygen levels. As you noted, people with COPD have lower blood oxygen levels (though you didn't say that specifically). Also, it's not "suddenly passing out." It's not feeling right, then getting dizzy, and then passing out ('fainting'). Many older people have this symptom progression while wearing masks without getting all the way to passing out.

Carbon dioxide molecules are significantly smaller than the holes in masks so the mask shouldn't stop it from passing through so this can't be true.

 

[Dhersh]

Carbon dioxide molecules are significantly smaller than the holes in masks so the mask shouldn't stop it from passing through so this can't be true.

Thanks I was about to say this earlier but got busy. CO2 molecules are significantly smaller than SARS-CoV-2. Anyone who subscribes to the theory that mask pores are too large to stop SARS-CoV-2 must subscribe to the theory that CO2 cannot build up in the mask.

 

[PopsNole]

Thanks I was about to say this earlier but got busy. CO2 particles are significantly smaller than SARS-CoV-2 molecules. Anyone who subscribes to the theory that mask pores are too large to stop SARS-CoV-2 molecules must subscribe to the theory that CO2 cannot build up in the mask.

Verbal meme. Super hero sweating over which button to push. One said "Mask holes are too big to stop Covid." Second says "Carbon dioxide is building up in masks hurting people."

 

[Dhersh]

I stumbled upon this article and thought it was informative.

 

[buckeyenole]

Carbon dioxide molecules are significantly smaller than the holes in masks so the mask shouldn't stop it from passing through so this can't be true.

It not only "can't be true," it is true. Carbon dioxide does build up in masks. At least according to the CDC.

Carbon dioxide increases with face masks but remains below short-term NIOSH limits - PubMed

Although, significant increase in CO2 concentrations are noted with routinely used face-masks, the levels still remain within the NIOSH limits for short-term use. Therefore, there should not be a concern in their regular day-to-day use for healthcare providers. The clinical implications of...

pubmed.ncbi.nlm.nih.gov

Carbon dioxide increases with face masks but remains below short-term NIOSH limits​

Michelle S M Rhee 1, Carin D Lindquist 1, Matthew T Silvestrini 1, Amanda C Chan 2, Jonathan J Y Ong 2, Vijay K Sharma 3
Affiliations expand

• PMID: 33858372
• PMCID: PMC8049746
• DOI: 10.1186/s12879-021-06056-0

Free PMC article

Abstract​

Background and purpose: COVID-19 pandemic led to wide-spread use of face-masks, respirators and other personal protective equipment (PPE) by healthcare workers. Various symptoms attributed to the use of PPE are believed to be, at least in part, due to elevated carbon-dioxide (CO2) levels. We evaluated concentrations of CO2 under various PPE.
Methods: In a prospective observational study on healthy volunteers, CO2 levels were measured during regular breathing while donning 1) no mask, 2) JustAir® powered air purifying respirator (PAPR), 3) KN95 respirator, and 4) valved-respirator. Serial CO2 measurements were taken with a nasal canula at a frequency of 1-Hz for 15-min for each PPE configuration to evaluate whether National Institute for Occupational Safety and Health (NIOSH) limits were breached.
Results: The study included 11 healthy volunteers, median age 32 years (range 16-54) and 6 (55%) men. Percent mean (SD) changes in CO2 values for no mask, JustAir® PAPR, KN95 respirator and valve respirator were 0.26 (0.12), 0.59 (0.097), 2.6 (0.14) and 2.4 (0.59), respectively. Use of face masks (KN95 and valved-respirator) resulted in significant increases in CO2 concentrations, which exceeded the 8-h NIOSH exposure threshold limit value-weighted average (TLV-TWA). However, the increases in CO2 concentrations did not breach short-term (15-min) limits. Importantly, these levels were considerably lower than the long-term (8-h) NIOSH limits during donning JustAir® PAPR. There was a statistically significant difference between all pairs (p < 0.0001, except KN95 and valved-respirator (p = 0.25). However, whether increase in CO2 levels are clinically significant remains debatable.
Conclusion: Although, significant increase in CO2 concentrations are noted with routinely used face-masks, the levels still remain within the NIOSH limits for short-term use. Therefore, there should not be a concern in their regular day-to-day use for healthcare providers. The clinical implications of elevated CO2 levels with long-term use of face masks needs further studies. Use of PAPR prevents relative hypercapnoea. However, whether PAPR should be advocated for healthcare workers requiring PPE for extended hours needs to evaluated in further studies.

 

[SteveT1]

OSHA rule nonsensical. Either (a) mandate vaccine on employees, or; (b) give employee the choice between (i) vaccine and (ii) weekly negative test + mask indoors. The rule will get torched in courts, imo.

 

[Dhersh]

A recent systematic review and meta-analysis study published in the British Medical Journal today.

Eligibility criteria for study selection:
Observational and interventional studies that assessed the effectiveness of public health measures in reducing the incidence of covid-19, SARS-CoV-2 transmission, and covid-19 mortality.

Main outcome measures:
The main outcome measure was incidence of covid-19. Secondary outcomes included SARS-CoV-2 transmission and covid-19 mortality.

Results:
72 studies met the inclusion criteria, of which 35 evaluated individual public health measures and 37 assessed multiple public health measures as a “package of interventions.” Eight of 35 studies were included in the meta-analysis, which indicated a reduction in incidence of covid-19 associated with handwashing (relative risk 0.47, 95% confidence interval 0.19 to 1.12, I2=12%), mask wearing (0.47, 0.29 to 0.75, I2=84%), and physical distancing (0.75, 0.59 to 0.95, I2=87%). Owing to heterogeneity of the studies, meta-analysis was not possible for the outcomes of quarantine and isolation, universal lockdowns, and closures of borders, schools, and workplaces. The effects of these interventions were synthesised descriptively.

Conclusions:
This systematic review and meta-analysis suggests that several personal protective and social measures, including handwashing, mask wearing, and physical distancing are associated with reductions in the incidence covid-19. Public health efforts to implement public health measures should consider community health and sociocultural needs, and future research is needed to better understand the effectiveness of public health measures in the context of covid-19 vaccination.

So it found it found a 53% reduction in COVID-19 incidence.

Additionally:
Mask wearing and transmission of SARS-CoV-2, covid-19 incidence, and covid-19 mortality—The results of additional studies that assessed mask wearing (not included in the meta-analysis because of substantial differences in the assessed outcomes) indicate a reduction in covid-19 incidence, SARS-CoV-2 transmission, and covid-19 mortality.