Department of Health, CDC: Community use of masks works to control spread of COVID-19 – The Stanly News & Press


The following release is from the Stanly County Health Department:

On Monday, the Center for Disease Control and Prevention provided a science briefing on community use of masks to control the spread of SARS-CoV-2. At least 10 studies in several countries, including the United States, have confirmed the benefit of universal masking in community-level analysis. Experimental and epidemiological data support community masking to reduce the spread of SARS-CoV-2, including alpha and delta variants, in adults and children. The preventative benefit of masking stems from the combination of source control and wearer protection.

SARS-CoV-2 infection is spread primarily by inhaling respiratory droplets generated when people cough, sneeze, sing, speak, or breathe. Multi-layered fabric masks block the release of exhaled respiratory particles into the environment, as well as the microorganisms associated with these particles. Sheet masks not only effectively block most large droplets (i.e. volume of speech and specific types of phonation. Multi-layered fabric masks can both block 50-70% of these fine droplets and particles and limit the flow. forward spread of those that are not captured.Over 80% blocking has been obtained in human experiments, with cloth masks in some studies performing on par with surgical masks as barriers for source control.

Studies show that fabric mask materials can also reduce wearer exposure to infectious droplets through filtration, including filtration of fine droplets and particles smaller than 10 microns. The relative filtration efficiency of various masks varied considerably from study to study, largely due to variation in experimental design and the size of the particles analyzed. Multiple layers of fabric with higher thread counts have demonstrated superior performance over single layers of fabric with lower thread counts, in some cases filtering out nearly 50 percent of fine particles less than 1 micron.

Research also confirms that under most circumstances wearing a mask does not have significant adverse effects on the health of wearers. Studies of healthy hospital workers, the elderly, and adults with chronic obstructive pulmonary disease (COPD) have reported little or no changes in oxygen or carbon dioxide levels when wearing a tissue or surgical mask during rest or moderate physical activity. Additionally, a study of 60 elementary school children reported no cardiovascular (eg, heart rate) or pulmonary (eg, peripheral oxygen saturation) effects in children wearing fabric face covers. in a classroom for 30 consecutive minutes of instruction. A separate study observed no oxygen desaturation or respiratory distress after 60 minutes of monitoring in children under 2 years old when masked during normal play. A randomized trial involving 40 children aged 3 to 10 years undergoing elective surgery found that protective surgical masks could be used safely in the postoperative period. In a prospective school-based cohort study of children aged 10 to 17 who wore masks for 6-7 hours during the school day, some children reported being general (4-7%) or situation-specific ( 2 to 4%). side effects such as skin irritation, headache or difficulty breathing during physical education.

https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/masking-science-sars-cov2.html