Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients

Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (S.B., J.Y.K., H.C., J.J., M.K., D.K.O., S.H., S.K.)

Chung-Ang University Hospital, Seoul, South Korea (M.K., M.L., S.C., J.C.)

Clinical Research Center, Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.S.L.)

Sejong University, Seoul, South Korea (M.S.)

Note: Authors indicated with an asterisk (Drs. Bae, M.-C. Kim, and J.Y. Kim) contributed equally to this article.

Acknowledgment: The authors thank patients who participated in this study.

Financial Support: By a grant from the Government-wide R&D Fund Project for Infectious Disease Research (GFID), Republic of Korea (grant HG18C0037).

Disclosures: None. Forms can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M20-1342.

Reproducible Research Statement: Study protocol, statistical code, and data set: Available from Dr. Sung-Han Kim (e-mail, [email protected]).

Corresponding Author: Sung-Han Kim, MD, Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea; e-mail, [email protected].

Transill on April 7th, 2020 at 01:46 UTC »

Cambridge did a study showing 1 layer of cotton filter 69% and 2 layers 71% while being twice as easy to breath through as surgical masks. Tea towels were the best at 74% single and 97% double but were twice as hard to breath through as surgical. So they arent perfect, but better than nothing...

Bizzle_worldwide on April 6th, 2020 at 22:36 UTC »

“We do not know whether masks shorten the travel distance of droplets during coughing. “

This is the key thing with all of these studies. Unsealed masks not rated for small particles aren’t going to filter out COVID19. But if they can slow down the velocity of travel at the mask, and cause it to have a projection of, say, 2-3 feet instead of 6-27 feet, that would significantly reduce transmission in environments like grocery stores.

Additionally, for healthy people, wearing a mask has a number of potential benefits, including slight filtration and reduction of exposed skin on the face for particles on land on. They can also reduce your touching your face and mouth.

greypowerOz on April 6th, 2020 at 22:12 UTC »

Actual Title: Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients

This experiment did not include N95 masks and does not reflect the actual transmission of infection from patients with COVID-19 wearing different types of masks. We do not know whether masks shorten the travel distance of droplets during coughing.

Further study is needed to recommend whether face masks decrease transmission of virus from asymptomatic individuals or those with suspected COVID-19 who are not coughing.

In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.

Nobody thinks masks will PREVENT the spread as far as I know. They merely "reduce" the risk.