Not a difficult study. Statistical analysis of infection rates as compared to countries with vs without masks.
Once they have this data they extrapolate and isolate certain variables unrelated to masks and perform a regressive analysis. Then you have your answer
Statistics/data analysis has been adequately conducted pertaining to far more complex issues.
Quoted for truth. 
Have you heard of or seen the PWI forum?
Something tells me you’ll love it. 
Fair enough. I’ll concede that the first year after 9/11 he was in the upper percentile of popularity. BUT, after the first 4 years of his presidency, his approval ratings dipped down to the 30ish% range.
It started dipping in 2005 and downwards. The after 2008, it dipped as low as 25%.
1. PMID: 19216002
Use of surgical face masks to reduce the incidence of the common cold among health care workers in Japan: a randomized controlled trial
Objective: Health care workers outside surgical suites in Asia use surgical-type face masks commonly. Prevention of upper respiratory infection is one reason given, although evidence of effectiveness is lacking.
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).
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.
2. PMID: 20092668
Face masks to prevent transmission of influenza virus: a systematic review
Objective: Many national and international health agencies recommended the use of face masks during the 2009 influenza A (H1N1) pandemic. We reviewed the English-language literature on this subject to inform public health preparedness.
Results: There is some evidence to support the wearing of masks or respirators during illness to protect others, and public health emphasis on mask wearing during illness may help to reduce influenza virus transmission. There are fewer data to support the use of masks or respirators to prevent becoming infected.
Conclusion: Further studies in controlled settings and studies of natural infections in healthcare and community settings are required to better define the effectiveness of face masks and respirators in preventing influenza virus transmission.
3. PMID: 22188875
The use of masks and respirators to prevent transmission of influenza: a systematic review of the scientific evidence
Objective: There are limited data on the use of masks and respirators to reduhce transmission of influenza. A systematic review was undertaken to help inform pandemic influenza guidance in the United Kingdom.
Results: Six of eight randomised controlled trials found no significant differences between control and intervention groups (masks with or without hand hygiene; N95/P2 respirators)…. 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)….however, these estimates were derived from the analyses of six SARS studies whose methodology was problematic.
Conclusion: None of the studies established a conclusive relationship between mask/respirator use and protection against influenza infection…. There is a limited evidence base to support the use of masks and/or respirators in healthcare or community settings.
4. PMID: 15340662
The physiological impact of wearing an N95 mask during hemodialysis as a precaution against SARS in patients with end-stage renal disease
Objective: This study investigated the physiological impact of wearing an N95 mask during hemodialysis (HD) on patients with ESRD.
Corona Mask Mandates: Science or Political Dogma?
Results: Thirty nine patients (23 men; mean age, 57.2 years) were recruited for participation in the study. Seventy percent of the patients showed a reduction in partial pressure of oxygen (PaO2), and 19% developed various degrees of hypoxemia.
Conclusion: Wearing an N95 mask for 4 hours during HD significantly reduced PaO2 and increased respiratory adverse effects in ESRD patients.
5. PMID: 32406064
Short-term skin reactions following use of N95 respirators and medical masks
Objective: To analyze the short-term effects of N95 respirators and medical masks, respectively, on skin physiological properties and to report adverse skin reactions caused by the protective equipment.
Results: Skin hydration, TEWL, and pH increased significantly with wearing the protective equipment. Erythema values increased from baseline. Sebum secretion increased both on the covered and uncovered skin with equipment-wearing.
Conclusions: This study demonstrates that skin biophysical characters change as a result of wearing a mask or respirator. N95 respirators were associated with more skin reactions than medical masks.
6. PMID: 32285928 (full Paper on ViaMedica Journals)
Cloth masks versus medical masks for COVID-19 protection
Objective: Global shortage of medical masks is a real and expanding problem. In turn, there is growing availability on the market of cloth masks. This is a study on the comparison of the efficacy of cloth masks to medical masks in the context of viral infections.
Results: Laboratory tests showed the penetration of particles through the cloth masks to be very high (97%) compared with medical masks (44%). A consequence of the above penetration is also a higher risk of critical care illness, the influenza- -like illness is more significant in the cloth mask group than in the medical mask. Moreover, the rate of confirmation of laboratory-confirmed viruses was also much higher for cloth masks than for medi- cal masks or groups that did not wear any mask.
Conclusion: Cloth masks don’t protect as well as medical masks. Moreover, the physical properties of a cloth mask, reuse, the frequency and effectiveness of cleaning, and increased moisture retention, may potentially increase the infection risk, since, as it indicated by Osterholm et al. [7] the virus may survive on the surface of the face- masks. In this context self-contamination through repeated use and improper doffing is possible. Observations during SARS suggested double-masking and other practices increased the risk of infection because of moisture, liquid diffusion and pathogen retention [8].
7. PMID: 25903751
A cluster randomised trial of cloth masks compared with medical masks in healthcare workers
Objective: The aim of this study was to compare the efficacy of cloth masks to medical masks in hospital healthcare workers (HCWs). The null hypothesis is that there is no difference between medical masks and cloth masks.
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…. 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.
8. PMID: 32513410
A study on infectivity of asymptomatic SARS-CoV-2 carriers
Objective: It is debatable whether asymptomatic COVID-19 virus carriers are contagious. We report here a case of the asymptomatic patient and present clinical characteristics of 455 contacts, which aims to study the infectivity of asymptomatic carriers.
Results: The median contact time for patients was four days and that for family members was five days…. The blood counts in most contacts were within a normal range. All CT images showed no sign of COVID-19 infection. No severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections was detected in 455 contacts by nucleic acid test.
Conclusion: In summary, all the 455 contacts were excluded from SARS-CoV-2 infection and we conclude that the infectivity of some asymptomatic SARS-CoV-2 carriers might be weak.
Not really heard of the PWI forum. What is that about.
CDC Website: a May 2020 study published in Emerging Infectious Diseases did a systematic review of 10 RCT’s on masks from 1946-2018. That’s a period of over 70 years. Results:
“In pooled analysis, we found no significant reduction in influenza transmission with the use of face masks…either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure…Proper use of face masks is essential because improper use might increase the risk of transmission.”
Canadian Family Physician in July 2020 published a study that conducted a “PEER umbrella systematic review” that included 11 systematic reviews and 18 RCTs involving a combined total of 26,444 participants in both clinical and community settings. Results:
Synthesis: “Overall, the use of masks in the community did not reduce the risk of influenza, confirmed viral respiratory infection, influenzalike illness, or any clinical respiratory infection.”
Review of the Medical Literature
Here are key anchor points to the extensive scientific literature that establishes that wearing
surgical masks and respirators (e.g., “N95”) does not reduce the risk of contracting a verified
illness:
Jacobs, J. L. et al. (2009) “Use of surgical face masks to reduce the incidence of the
common cold among health care workers in Japan: A randomized controlled trial”,
American Journal of Infection Control, Volume 37, Issue 5, 417 - 419.
N95-masked health-care workers (HCW) were significantly more likely to
experience headaches. Face mask use in HCW was not demonstrated to provide
benefit in terms of cold symptoms or getting colds.
Cowling, B. et al. (2010) “Face masks to prevent transmission of influenza virus: A
systematic review”, Epidemiology and Infection, 138(4), 449-456.
doi:10.1017/S0950268809991658
https://www.cambridge.org/core/journals/epidemiology-and-infection/article/facemasks-to-prevent-transmission-of-influenza-virus-a-systematicreview/64D368496EBDE0AFCC6639CCC9D8BC05
None of the studies reviewed showed a benefit from wearing a mask, in either
HCW or community members in households (H). See summary Tables 1 and 2
therein.
bin-Reza et al. (2012) “The use of masks and respirators to prevent transmission of
influenza: a systematic review of the scientific evidence”, Influenza and Other
Respiratory Viruses 6(4), 257–267.
https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1750-2659.2011.00307.x
“There were 17 eligible studies. … None of the studies established a conclusive
relationship between mask ⁄ respirator use and protection against influenza
infection.”
Smith, J.D. et al. (2016) “Effectiveness of N95 respirators versus surgical masks in
protecting health care workers from acute respiratory infection: a systematic review and
meta-analysis”, CMAJ Mar 2016, cmaj.150835; DOI: 10.1503/cmaj.150835
https://www.cmaj.ca/content/188/8/567
“We identified 6 clinical 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, (b)
influenza-like illness, or (c) reported work-place absenteeism.”3
Offeddu, V. et al. (2017) “Effectiveness of Masks and Respirators Against Respiratory
Infections in Healthcare Workers: A Systematic Review and Meta-Analysis”, Clinical
Infectious Diseases, Volume 65, Issue 11, 1 December 2017, Pages 1934–1942,
https://doi.org/10.1093/cid/cix681
https://academic.oup.com/cid/article/65/11/1934/4068747
“Self-reported assessment of clinical outcomes was prone to bias. Evidence of a
protective effect of masks or respirators against verified respiratory infection
(VRI) was not statistically significant”; as per Fig. 2c therein:
Radonovich, L.J. et al. (2019) “N95 Respirators vs Medical Masks for Preventing
Influenza Among Health Care Personnel: A Randomized Clinical Trial”, JAMA. 2019;
322(9): 824–833. doi:10.1001/jama.2019.11645
N95 Respirators vs Medical Masks for Preventing Laboratory-Confirmed Influenza in Health Care Personnel
“Among 2862 randomized participants, 2371 completed the study and
accounted for 5180 HCW-seasons. … 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.”
Long, Y. et al. (2020) “Effectiveness of N95 respirators versus surgical masks against
influenza: A systematic review and meta‐analysis”, J Evid Based Med. 2020; 1‐ 9.
https://doi.org/10.1111/jebm.12381
https://onlinelibrary.wiley.com/doi/epdf/10.1111/jebm.12381
“A total of six RCTs involving 9 171 participants were included. There were no
statistically significant differences in preventing laboratory‐confirmed influenza,
laboratory‐confirmed respiratory viral infections, laboratory‐confirmed
respiratory infection and influenza-like illness using N95 respirators and surgical
masks. Meta‐analysis indicated a protective effect of N95 respirators against
laboratory‐confirmed bacterial colonization (RR = 0.58, 95% CI 0.43‐0.78). The 4
use of N95 respirators compared with surgical masks is not associated with a
lower risk of laboratory‐confirmed influenza.
So far, most studies found little to no evidence for the effectiveness of cloth face masks in the general population, neither as personal protective equipment nor as a source control.
In many states, coronavirus infections strongly increased after mask mandates had been introduced. The following charts show the typical examples of Austria, Belgium, France, Germany, Ireland, Italy, Spain, the UK, California and Hawaii. Furthermore, a direct comparison between US states with and without mask mandates indicates that mask mandates have made no difference.
Ah! Here ya go.
Now you and @bloomdid can run wild and free.
1. Insubstantial: A CDC-funded review on masking in May 2020 came to the conclusion: “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… None of the household studies reported a significant reduction in secondary laboratory-confirmed influenza virus infections in the face mask group.” If masks can’t stop the regular flu, how can they stop SAR-CoV-2?
2. Unreasonable: “Evidence that masking as a source [of] control results in any material reduction in transmission was scant, anecdotal, and, in the overall, lacking… [and mandatory masking] is the exact opposite of being reasonable,” ruled a hospital arbitrator in a dispute between The Ontario Nurses’ Association and the Toronto Academic Health Science Network.
3. Ineffective: “Oral masks in healthy individuals are ineffective against the spread of viral infections,” write Belgian medical doctors in an open letter published in The American Institute of Stress , September 24, 2020.
4. Unsanitary: “It has never been shown that wearing surgical face masks decreases postoperative wound infections,” writes Göran Tunevall, M.D. in the World Journal of Surgery . “On the contrary, a 50% decrease [in bacterial infection] has been reported after omitting face masks.”
5. No Protection: “There were 17 eligible studies.… None of the studies established a conclusive relationship between mask ⁄ respirator use and protection against influenza infection,” concludes a research review in the journal Influenza and Other Respiratory Viruses .
6. Unproven: Dutch Minister for Medical Care, Tamara van Ark, asserted that “from a medical perspective there is no proven effectiveness of masks” after a review by the National Institute for Health on July 29, 2020 (according to Reuters ).
A May 12, 2020 article published in the peer review journal Health Affairs emphatically states: “Experts reviewing the evidence from 1918 concluded that flu masks failed to control infection.” The article goes on to cite a 1919 study by Wilfred H. Kellogg for the California State Board of Health: “…mask ordinances applied forcibly to entire communities did not decrease cases and deaths, as confirmed by comparisons of cities with widely divergent policies on masking.” Kellogg concluded: “The case against the mask as a measure of compulsory application for the control of epidemics appears to be complete.” Two other studies cited in the article, one from 1918 and another from 1921, reached the same conclusion.
masks-dont-work-denis-rancourt-april-2020.pdf (vaccinechoicecanada.com)
Balazy et al. (2006) “Do N95 respirators provide 95% protection level against airborne viruses,
and how adequate are surgical masks?”, American Journal of Infection Control, Volume 34,
Issue 2, March 2006, Pages 51-57. doi:10.1016/j.ajic.2005.08.018
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.488.4644&rep=rep1&type=pdf
Davies, A. et al. (2013) “Testing the Efficacy of Homemade Masks: Would They Protect in an
Influenza Pandemic?”, Disaster Medicine and Public Health Preparedness, Available on CJO
2013 doi:10.1017/dmp.2013.43
Lai, A. C. K. et al. (2012) “Effectiveness of facemasks to reduce exposure hazards for airborne
infections among general populations”, J. R. Soc. Interface. 9938–948
Leung, N.H.L. et al. (2020) “Respiratory virus shedding in exhaled breath and efficacy of face
masks”, Nature Medicine (2020). Respiratory virus shedding in exhaled breath and efficacy of face masks | Nature Medicine
So you asserted something like: “masks don’t work to prevent Covid”.
No conclusion can be drawn from this study to support your assertion.
Same with this one.
Same here. I think you are making an error by conflating a study not concluding that masks are effective being the same as “masks are not effective”. Those are separate things.
Skipped the next two as they were not related to efficacy of the mask in virus prevention.
This study supports the opposite of your assertion. It suggests that medical masks can protect one from virus transmission if used properly.
This seems to suggest what you are asserting is correct, but when we look at the objective, it is only comparing risk of cloth vs medical mask.
So we can conclude that cloth is worse than medical masks, but not that they are not effective in general.
One stat for you on mask effectiveness. Typically each year the US has about 40,000 deaths from the flu. We had 7,500 last year. That is a 5X reduction in flu deaths. We wore masks, and we see flu deaths drop off a cliff. Sure we stayed home more, but IMO, a portion of the 5X drop in flu deaths were from mask wearing.
Ah ha! I see. I don’t know if I have enough stamina to do all of that. LOL
Might I just add that these are indeed interesting points made on both sides of the isle. It is telling to see how a lot of people feel about the mask issue.
Once again just guessing, but I doubt that would be a problem.
(I am a pretty good guesser though.)
That’s not hard but it is also not that great a standard of evidence either and it I don’t think it answers the question.
Conclusion regarding masks that do not work
No RCT study with verified outcome shows a benefit for HCW or community members in households to wearing a mask or respirator. There is no such study. There are no exceptions. Likewise , no study exists that shows a benefit from a broad policy to wear masks in public (more on this below).
Furthermore, if there were any benefit to wearing a mask, because of the blocking power against droplets and aerosol particles, then there should be more benefit from wearing a respirator (N95) compared to a surgical mask, yet several large meta-analyses, and all the RCT, prove that there is no such relative benefit . Masks and respirators do not work.
Precautionary Principle turned on its head with masks
In light of the medical research, therefore, it is difficult to understand why public-health authorities are not consistently adamant about this established scientific result, since the distributed psychological, economic and environmental harm from a broad recommendation to wear masks is significant, not to mention the unknown potential harm from concentration and distribution of pathogens on and from used masks.
In this case, public authorities would be turning the precautionary principle on its head (see below).
Physics and Biology of Viral Respiratory Disease, and why masks do not work
In order to understand why masks cannot possibly work, we must review established knowledge about viral respiratory diseases, the mechanism of seasonal variation of excess deaths from pneumonia and influenza, the aerosol mechanism of infectious disease transmission, the physics and chemistry of aerosols, and the mechanism of the so-called minimum-infective-dose.
In addition to pandemics that can occur anytime, in the temperate latitudes there is an extra burden of respiratory-disease mortality that is seasonal, and which is caused by viruses. For example, see the review of influenza by Paules and Subbarao (2017). This has been known for a long time, and the seasonal pattern is exceedingly regular .
For example, see Figure 1 of Viboud (2010), which has “Weekly time series of the ratio of deaths from pneumonia and influenza to all deaths, based on the 122 cities surveillance in the US (blue line). The red line represents the expected baseline ratio in the absence of influenza activity,” here:
The seasonality of the phenomenon was largely not understood until a decade ago. Until recently, it was debated whether the pattern arose primarily because of seasonal change in virulence of the pathogens, or because of seasonal change in susceptibility of the host (such as from dry air causing tissue irritation, or diminished daylight causing vitamin deficiency or hormonal stress). For example, see Dowell (2001).
In a landmark study, Shaman et al. (2010) showed that the seasonal pattern of extra respiratory-disease mortality can be explained quantitatively on the sole basis of absolute humidity, and its direct controlling impact on transmission of airborne pathogens .
Lowen et al. (2007) demonstrated the phenomenon of humidity-dependent airborne-virus virulence in actual disease transmission between guinea pigs, and discussed potential underlying mechanisms for the measured controlling effect of humidity.
The underlying mechanism is that the pathogen-laden aerosol particles or droplets are neutralized within a half-life that monotonically and significantly decreases with increasing ambient humidity. This is based on the seminal work of Harper (1961). Harper experimentally showed that viral-pathogen-carrying droplets were inactivated within shorter and shorter times, as ambient humidity was increased .
Harper argued that the viruses themselves were made inoperative by the humidity (“viable decay”), however, he admitted that the effect could be from humidity-enhanced physical removal or sedimentation of the droplets (“physical loss”): “Aerosol viabilities reported in this paper are based on the ratio of virus titre to radioactive count in suspension and cloud samples, and can be criticized on the ground that test and tracer materials were not physically identical.”
The latter (“physical loss”) seems more plausible to me, since humidity would have a universal physical effect of causing particle / droplet growth and
sedimentation, and all tested viral pathogens have essentially the same humidity-driven “decay”. Furthermore, it is difficult to understand how a virion (of all virus types) in a droplet would be molecularly or structurally attacked or damaged by an increase in ambient humidity. A “virion” is the complete, infective form of a virus outside a host cell, with a core of RNA or DNA and a capsid. The actual mechanism of such humidity-driven intra-droplet “viable decay” of a virion has not been explained or studied.
In any case, the explanation and model of Shaman et al . (2010) is not dependant on the particular mechanism of the humidity-driven decay of virions in aerosol / droplets. Shaman’s quantitatively demonstrated model of seasonal regional viral epidemiology is valid for either mechanism (or combination of mechanisms), whether “viable decay” or “physical loss”.
The breakthrough achieved by Shaman et al. is not merely some academic point. Rather, it has profound health-policy implications, which have been entirely ignored or overlooked in the current coronavirus pandemic.
In particular, Shaman’s work necessarily implies that, rather than being a fixed number (dependent solely on the spatial-temporal structure of social interactions in a completely susceptible population, and on the viral strain), the epidemic’s basic reproduction number (R0) is highly or predominantly dependent on ambient absolute humidity .
For a definition of R0, see HealthKnowlege-UK (2020): R0 is “the average number of secondary infections produced by a typical case of an infection in a population where everyone is susceptible.” The average R0 for influenza is said to be 1.28 (1.19-1.37); see the comprehensive review by Biggerstaff et al. (2014).
In fact, Shaman et al. showed that R0 must be understood to seasonally vary between humid-summer values of just larger than “1” and dry-winter values typically as large as “4” (for example, see their Table 2). In other words, the seasonal infectious viral respiratory diseases that plague temperate latitudes every year go from being intrinsically mildly contagious to virulently contagious, due simply to the bio-physical mode of transmission controlled by atmospheric humidity, irrespective of any other consideration .
Therefore, all the epidemiological mathematical modelling of the benefits of mediating policies (such as social distancing), which assumes humidity-independent R0 values, has a large likelihood of being of little value, on this basis alone . For studies about modelling and regarding mediation effects on the effective reproduction number, see Coburn (2009) and Tracht (2010).
To put it simply, the “second wave” of an epidemic is not a consequence of human sin regarding mask wearing and hand shaking . Rather, the “second wave” is an inescapable consequence of an air-dryness-driven many-fold increase in disease contagiousness, in a population that has not yet attained immunity.
So far, most studies found little to no evidence for the effectiveness of cloth face masks in the general population, neither as personal protective equipment nor as a source control.
In many states, coronavirus infections strongly increased after mask mandates had been introduced. The following charts show the typical examples of Austria, Belgium, France, Germany, Ireland, Italy, Spain, the UK, California and Hawaii. Furthermore, a direct comparison between US states with and without mask mandates indicates that mask mandates have made no difference.
Ya know, this did morph into a PWI thread. I’ll let it move on there.
That’s what pisses me off about this whole thing. How do people mange to turn a f-ing public health issue into a political issue.
On the topic of masks in the gym- it sucks but isn’t dangerous
