Scientific papers show
masks reduce virus spread
The coronavirus enters the body through the nose and mouth. So it makes sense that masks would limit infection rates; but do any studies demonstrate that masks help?
Jeremy Howard, an Australian data scientist, found 34 papers that support mask effectiveness and none that refute it. The National Institutes of Health presented a visual using laser light to demonstrate the spread of droplets when someone speaks (6 feet). Nearly all were blocked by a mask. In Hong Kong and Taiwan, where mask wearing is near 100%, the total death count from COVID-19 was fewer than 10, despite high population density. Countries that have flattened the infection curve used masks in public.
How about the wearer? The World Health Organization found in the review of 64 scientific papers that masks dropped the wearer’s infection rate by 50% to 80%. Considering the diversity of materials, this is relevant. They also found that due to lower viral intake, those who did contract the virus did not get as sick.
Researchers in Hong Kong studied transmission rates by placing healthy hamsters in one cage and infected hamsters in an adjacent cage with a fan blowing toward the cage containing the healthy hamsters. They studied infection rates with neither cage covered; with only the infected cage covered; and with only the healthy cage covered. The infection rate among the healthy hamsters was 67% with no cover. They found that with mask material covering the infected cage, the infection rate dropped to 17%. When the mask material was placed on the healthy cage, the rate fell to 33%. Also, the hamsters that did become infected had lower viral loads.
Unfortunately, masks have become a political statement. We see the infection rate rise, as shown by intensive care unit and hospitalization rates, not just testing. If you wish to make a statement, wear a hat or T-shirt in addition to a mask. The people around you cannot help the economy from a hospital bed.
J.L. Bayer, D.V.M.