8/11/20: COVID-19 UPDATE: 15 NEW CASES REPORTED, INCLUDING HOSPITALIZED DARE COUNTY MAN, 65+. Plus Duke Researchers Show Bandanas, Gaiters Don’t Cut It.  

facemasks
Duke University scientists tested 14 different face masks, pictured above, for their efficacy in filtering expelled respiratory droplets during the wearer’s speech.  (Photo by Emma Fischer of Duke University.) 

A Dare County man in the 65-or-older age group who has been hospitalized is among the 15 people who have tested positive locally for COVID-19 since last Friday, according to the Dare County Dept. of Health and Human Services, which issued an update today.

The local man’s hospitalization outside of the area was reported by the DCDHHS Sunday. On Saturday the DCDHHS reported that another Dare County man, who is between the ages of 50 and 64, also had to be hospitalized for COVID-19.

Of the 13 other new COVID-19 cases diagnosed since last Friday’s DCDHHS update, 12 are nonresidents; and of these 12, the DCDHHS reported today, 11 acquired the virus by direct contact with an individual who either tested positive outside of Dare County (seven) or acquired the virus outside of Dare County (four).

The mode of transmission of the thirteenth is unclear, an “indication” of community spread, according to the DCDHHS.

We frankly do not understand how useful it is to the Dare County public to know that a nonresident had direct contact with a person who “tested positive for COVID-19” outside of Dare County, as opposed to direct contact with a person “who acquired the virus” outside of Dare County. The DCDHHS should explain this distinction, if it is significant.

The Beacon reported Friday on the seven nonresidents whose positive COVID-19 test results made the DCDHHS dashboard that day. Another non-resident case was reported on the dashboard yesterday.

The COVID-19 cases of the four remaining nonresidents, including two who are age 17 or younger, were reported today. These two young people are isolating in Dare County. Today’s other two cases transferred to isolation in their home counties. One is between the ages of 18 and 24, and the other is between the ages of 50 and 64.

The total number of COVID-19 cases diagnosed in Dare County is now 384, of whom 210 are residents and 174 nonresidents.

There currently are two Dare County residents and two nonresidents hospitalized for COVID-19, according to the DCDHHS dashboard.

SORRY, KIDS, BANDANAS DON’T CUT IT

Duke University researchers tested 14 different face masks or mask alternatives to find out how effective they are in reducing the transmission of respiratory droplets during regular speech and discovered that fitted N95 masks and surgical masks worn by healthcare workers are the most effective and “mask alternatives, such as neck fleece or bandanas, offer very little protection.”

Neck fleeces—also called gaiters—actually provided worse protection than not wearing a mask at all because they dispersed the wearer’s largest respiratory droplets into “a multitude of smaller droplets,” the research team wrote in its study report, and “smaller particles are airborne longer than large droplets,” which sink faster.

The Duke study, titled “Low-Cost Measurement of Facemask Efficacy for Filtering Expelled Droplets During Speech,” was published online Aug. 7 in Science Advances, and may be accessed at https://advances.sciencemag.org/content/early/2020/08/07/sciadv.abd3083.

We will give more details tomorrow about the Duke study, which used a simple, inexpensive optical measurement method to evaluate the masks. Amateur physicists can easily re-create their experimental setup.

Ann G. Sjoerdsma, 8/11/20

 

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