Here’s a quick cruise through some of the science of masks. Perhaps the most important study says this:
Neither surgical nor cotton masks effectively filtered SARS–CoV-2 during coughs by infected patients.
Unfortunately, that’s the main basis used to sell masks to the public—that masks are mostly not for uninfected people to protect themselves, but to prevent infected people from infecting others …
… except the study says that masks don’t prevent viral spread from infected people in any meaningful way.
Onwards … below are the studies (emphasis in all cases is mine). Please be clear, I am not on either Team Mask or Team No-Mask. I wear one sometimes, and not other times. It’s a proper N-95 mask. I make no pretense that these are all the studies, there are many more, and there are experts on both sides of the question taking diametrically opposite positions. Here are some of them.
The University of New South Wales said the use of cloth masks by healthcare workers may put them at increased risk of respiratory illness and viral infections, and their global use should be discouraged. They reported that cloth masks are only marginally beneficial in protecting individuals from particles less than 2.5 micrometers. As referenced in the New England Journal of Medicine, the size of Coronavirus particles varied between 0.06 micrometers and 0.14 micrometers.
The study found respiratory infection was much higher among healthcare workers wearing cloth masks.
The penetration of cloth masks by particles was almost 97% compared to medical masks with 44%.
Professor Raina MacIntyre, lead study author and head of UNSW’s School of Public Health and Community Medicine, said the results of the study caution against the use of cloth masks.
In the British Medical Journal a 2015 study says that contaminated masks and masks holding moisture and pathogen retention can increase the risk of infection.
“… over three times the risk of contracting influenza-like illness if a cloth mask is used versus no mask at all.”
That is to say, not only did the masks not protect the wearers—the masks actually made the wearers sicker …
Next, cloth and surgical masks do not have a fit test. When worn, gaps around the edges allow small particles to enter the respiratory system, as well as to leave the mask. This is a known problem with no easy answer.
Also, according to the May 2010 edition of PLoS One, lack of eye protection was a primary risk factor of SARS-CoV transmission.
In Epidemics 2017, a meta-analysis of a number of studies concluded that masks made little difference, viz:
We review the effectiveness of PPMs against pandemic influenza infection.
Hand hygiene provided a significant protective effect.
Facemask use provided a non-significant protective effect.
A “non-significant protective effect” means the mask did NOT significantly protect the wearer.
Then we have a very important study in the Annuals of Internal Medicine, April 2020:
Discussion: Neither surgical nor cotton masks effectively filtered SARS–CoV-2 during coughs by infected patients. Prior evidence that surgical masks effectively filtered influenza virus (1) informed recommendations that patients with confirmed or suspected COVID-19 should wear face masks to prevent transmission (2). However, the size and concentrations of SARS–CoV-2 in aerosols generated during coughing are unknown. Oberg and Brousseau (3) demonstrated that surgical masks did not exhibit adequate filter performance against aerosols measuring 0.9, 2.0, and 3.1 μm in diameter. Lee and colleagues (4) showed that particles 0.04 to 0.2 μm can penetrate surgical masks. The size of the SARS–CoV particle from the 2002–2004 outbreak was estimated as 0.08 to 0.14 μm (5); assuming that SARS-CoV-2 has a similar size, surgical masks are unlikely to effectively filter this virus.
When infectious people cough, the virus escapes into the environment, mask or no mask. No surprise to me. No simple mask is going to be able to contain a cough or a sneeze. It just blows out all around the edges.
What is a surprise, to me at least, is that the coronavirus goes right through a surgical mask …
And in closing, the World Health Organization advises people to wear a mask, but only if they are displaying symptoms of Coronavirus or taking care of someone with COVID-19 infection. Here’s their graphic:
My conclusion from all of these studies on masks?
Stay well, dear friends, enjoy the sun, smell the flowers.