Clark County Public Health issued this statement today about a recent Center for Disease Control and Prevention report on mask effectiveness:
Last month, Centers for Disease Control and Prevention (CDC) issued a report looking at community exposures among people who tested positive for COVID-19 and a control group. Recently, the findings from that report have been misinterpreted and are being used to spread misinformation about the effectiveness of masks.
The report looked at community exposures among people who tested positive for COVID-19 and people who had symptoms but tested negative for COVID-19 (the control group). The report also included information about how often cases and non-cases reported wearing face coverings.
Most people in both groups reported always using masks in public. Even among people who always wear masks, there are activities where masks cannot be worn, such as while eating or drinking. The report showed that people who tested positive for COVID-19 were twice as likely to have reported dining at a restaurant in the two weeks before getting sick than those with negative test results.
The report did not include information about how often those same individuals reported wearing masks when gathering with others in private settings. In Clark County, exposure data shows that small private gatherings continue to be a common source of exposure to the virus that causes COVID-19.
The recommendation to wear face coverings is to protect others, not the person wearing the face covering. Face coverings work by blocking exhaled respiratory droplets. If the person wearing the face covering is infected with COVID-19, the mask can block those droplets from spreading the virus to others.
You can read the full CDC report here: https://www.cdc.gov/mmwr/volumes/69/wr/mm6936a5.htm?s_cid=mm6936a5_w
Learn more about the effectiveness of masks here: https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/cloth-face-cover-guidance.html#evidence-effectiveness