And a laboratory is NOT the real word. Talk about a "no shit sherlock" or 'stating the obvious. Why are people so dense? So blinded by what's right in front of them?
In controlled laboratory situations, face masks appear (appearances can be deceiving) to do a good job of reducing the spread of coronavirus (at least in hamsters) and other respiratory viruses. However, evidence shows mask-wearing policies seem to have had much less impact on the community spread of Covid-19.
Why this gap between the effectiveness in the lab and the effectiveness seen in the community? The real world is more complex than a controlled laboratory situation. The right people need to wear the right mask, in the right way, at the right times and places.
The real world is more complex?! Wow. No way. Again with the stating the obvious. Yet governments are doubling down on their own definition of insanity- masks and lock downs. Didn't work the first time. Won't work the second time. Unless they (the powers that very obviously shouldn't be) alter the CT values of the PCR tests. Then they can make the pandemic go away. Simply disappear it.
The real-world impact of face masks on the transmission of viruses depends not just on the behaviour of the virus but also on the behaviour of aerosol droplets in diverse settings, and on the behaviour of people themselves.
That a whole lot of variables... Real world kind of stuff, ya know?
We carried out a comprehensive review of the evidence about how face masks and other physical interventions affect the spread of respiratory viruses. Based on the current evidence, we believe the community impact is modest (non existent) and it may be better to focus on mask-wearing in high-risk situations.
Simply comparing infection rates in people who wear masks with those who don't can be misleading. One problem is people who don't wear masks are more likely go to crowded spaces, and less likely to socially distance. (That's a foolish assumption)
People who are more concerned often adhere to several protective behaviours ( More foolish assumptions) — they are likely to avoid crowds and socially distance as well as wearing masks.
When I don't wear a mask- I stay away from the freak outs. And shop when it's not busy. Meanwhile the freak out mask wearers are standing around talking up a storm. And shooting dirty looks to people without masks.
That correlation between mask wearing and other protective behaviours might explain why studies comparing mask-wearers with non-mask-wearers (known as "observational studies") show larger effects than seen in trials. Part of the effect is due to those other behaviours.
The most rigorous, but difficult, way to evaluate the effectiveness of masks is to take a large group of people and ask some to wear masks and others not to, in a so-called controlled trial. We found nine such trials have been carried out for influenza-like illness. Surprisingly, when combined, these trials found only a 1% reduction in influenza-like illness among mask-wearers compared with non-mask-wearers, and a 9% reduction in laboratory-confirmed influenza. These small reductions are not statistically significant, and are most likely due to chance.
Due to chance. And nothing more. Because there has never been any real science supporting mask wearing as a means to reduce viral spread. Check the spin below? There is no reason to believe that the Covid virus, which is similar in size to the influenza virus would result in any different outcome in a rigourous, real science based mask study.
None of these trials studied Covid-19, so we can't be sure how relevant they are to the pandemic. The SARS-CoV-2 coronavirus is a similar size to influenza, but has a different capacity to infect people, so it is possible masks might be more or less effective for Covid-19. A recently published trial in Denmark of 4862 adults found infection with SARS-CoV-2 occurred in 42 participants randomised to masks (1.8%) compared to 53 control participants (2.1%).
In the recent study from Denmark the masks were equally as ineffective as with the Coronavirus.
What might diminish the effect of masks?
Why might masks not protect the person wearing them? There are several possibilities. Standard masks only protect your nose and mouth incompletely, for one thing
Why masks might fail to clearly protect others is more complex. Good masks reduce the spread of droplets and aerosols, and so should protect others.
However, in our systematic review we found three trials that assessed how well mask wearing protects others, but none of them found an obvious effect. The two trials in households where a person with influenza wore a mask to protect others in fact found a slight increase in flu infections; and the third trial, in college dormitories, found a non-significant 10% relative reduction.
We don't know if the failure was the masks or participants' adherence. In most studies adherence was poor. In the trials very few people wear them all day (an average of about four hours by self-report, and even less when directly observed). And this adherence declined with time.
But we also have little research on how long a single mask is effective. Most guidelines suggest around four hours, but studies on bacteria show masks provide good protection for the first hour and by two hours are doing little. Unfortunately, we could not identify similar research examining viruses.
Is it better to focus masks on the 3 Cs: covered, crowded and close contact?
In addition to the completed Danish trial, another ongoing trial in Guinea-Bissau with 66,000 participants randomised as whole villages may shed more light as it tests the idea of source control. But given the millions of cases and billions of potential masks and mask wearers, more such trials are warranted.
We know masks are effective in laboratory studies, and we know they are effective as part of personal protective equipment for health care workers. But that effect appears diminished in community usage. So in addition to the trials, new research is urgently needed to unravel each of the reasons laboratory effectiveness does not seem to have translated into community effectiveness. We must also develop ways to overcome the discrepancy.
Until we have the needed research, we should be wary about relying on masks as the mainstay for preventing community transmission. And if we want people to wear masks regularly, we might do better to target higher-risk circumstances for shorter periods. These are generally places described by "the three Cs": crowded places, close-contact settings, and confined and enclosed spaces. These would include some workplaces and on public transport.
We are likely to be better off if we get high usage of fresh masks in the most risky settings, rather than moderate usage everywhere.
- Paul Glasziou is a Professor of Medicine at Bond University; Chris Del Mar is a Professor of Public Health at Bond University
Exactly as has been stated here and many other places. Repeatedly. False sense of security and possibility of making the spread worse. I will have more on the Denmark study... For now I'll close with Scott's latest video, below: