By Dr. Henning Ansorg, M.D., FACP, Health Officer County of Santa Barbara, Department of Public Health
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Did you know that wearing cloth face coverings is one of the most powerful tools we have to slow and stop the spread of the coronavirus? But as masks and face coverings become commonplace, so have questions about which mask is best, and the overall effectiveness of masks.
In a recently published study, by Science Advances, the researchers unveiled a simple method to evaluate the effectiveness of various types of masks, analyzing more than a dozen different facial coverings ranging from hospital-grade N95 respirators to bandanas.
Of the 14 masks and other coverings tested, the study found that some cotton cloth masks are about as effective as standard surgical masks, while popular alternatives such as neck gaiters are made out of a more porous material and therefore not as protective as double layered cotton masks. Having said that, masks do not have to be perfect to be effective. The more people wear a mask, the higher the level of protection is achieved for everyone.
It is important to first understand how the virus is transmitted and what masks are intended to do. According to the Centers for Disease Control (CDC) the purpose of wearing a mask is to keep respiratory droplets from reaching others to aid with source control.
The CDC says that masks are recommended as a simple barrier to help prevent respiratory droplets from traveling into the air and onto other people when the person wearing the mask coughs, sneezes, talks, or raises their voice. This is called source control.
We now have evidence that wearing a mask protects the wearer as well.
This recommendation is based on what we know about the role respiratory droplets play in the spread of the virus that causes COVID-19, paired with emerging evidence from clinical and laboratory studies that shows masks reduce the spray of droplets when worn over the nose and mouth. COVID-19 spreads mainly among people who are in close contact with one another (within about 6 feet), so the use of masks is particularly important in settings where people are close to each other or where social distancing is difficult to maintain.
Masks with one-way valves or vents allow air to be exhaled through a hole in the material, which can result in expelled respiratory droplets that can reach others. This type of mask does not prevent the person wearing the mask from transmitting COVID-19 to others and is not recommended by the CDC for source control.
- A face shield is primarily used for eye protection for the person wearing it. At this time, it is not known what level of protection a face shield provides to people nearby from the spray of respiratory droplets from the wearer. There is currently not enough evidence to support the effectiveness of face shields for source control. Therefore, CDC does not currently recommend use of face shields as a substitute for masks.
Please continue to wear a cloth face mask or surgical mask in public places and if you could get within six feet of others; it is one of the best ways we have to prevent spread of the virus.
Dr. Henning Ansorg, M.D., FACP is a graduate of Justus-Liebig-University Medical School Giessen, Germany. He completed Residency training in Munich, Germany and Tucson, AZ and is board certified in Family Practice (Germany) and Internal Medicine (USA). Dr. Ansorg is a Diplomate of the American Board of Internal Medicine and a Fellow of the American College of Physicians and is on the Medical Staff at Cottage Hospital in Santa Barbara. He has many years of experience in different clinical settings including 10 years of Private Practice and Urgent Care in Munich, Germany as well as 11 years of Internal Medicine/Geriatrics in Arizona as well as 4 years at the Santa Barbara County Health Care Center. Dr. Ansorg has served as Public Health Officer for Santa Barbara County since April 2019.