Jeremy Howard, a data research scientist who teaches at the University of San Francisco, along with 18 other professionals in a variety of disciplines, conducted a review of the research on wearing a mask to prevent the spread of COVID-19. They published a preprint of their paper on April 12 and it is now awaiting peer review at the Proceedings of the National Academy of Sciences.
What they found was strong evidence to support wearing masks in public. Howard said, “It appeared that universal mask-wearing could be one of the most important tools in tackling the spread of COVID-19.” The research scientist further stated that there have been many more reviews to substantiate the claim.
On May 14th, Howard along with 100 of the world’s top academics released an open letter to all U.S. governors asking that “officials require cloth masks to be worn in all public places, such as stores, transportation systems, and public buildings.”
The research that first persuaded Howard was a laser light-scattering experiment. Researchers from the National Institutes of Health used lasers to illuminate and count how many droplets of saliva went into the air by a person talking with and without a face mask. When the test subject used a simple cloth face cover, nearly all the droplets were blocked.
Although the experiment cannot see “micro-droplets” that are smaller than 5 microns and could contain some viral particles, virologists are unsure how much of a role these “micro” particles play in the transmission of COVID-19.
Recent research suggests that cloth masks are also effective at reducing the spread of these smaller particles. In a paper that has not yet been peer-reviewed, researchers found that micro-droplets fell out of the air within 1.5 meters of the person who was wearing a mask, versus 5 meters for those not wearing masks. Another recent study demonstrated that surgical masks are 100 percent effective in blocking droplets.
If only people with symptoms infected others, then only people with symptoms would need to wear masks. However, four recent studies show that nearly half of patients are infected by people who do not themselves have symptoms.
For people who wish to make their own masks, there is a company in Oklahoma that is selling non-washable nanofiber material that has nearly comparable filtration to an N95 mask. Here is a link to that company: filti.com
As you can see the scientific evidence is compelling. We should all wear masks and practice social distancing when out in public if we are to control this pandemic.
