Neither surgical nor cotton masks effectively filter Covid 19 virus: study

During respiratory viral infection, face masks are thought to prevent transmission, leading health care experts to recommend their use during the COVID-19 pandemic. With a shortage of both N95 and surgical masks, which have been shown to prevent the spread of influenza virus, cotton masks have gained interest as a substitute. However, it is not known if surgical or cotton masks worn by patients with COVID-19 prevent contamination of the environment.

Researchers from Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea instructed 4 patients with COVID-19 to cough 5 times each onto a petri dish while wearing the following sequence of masks: no mask, surgical mask, cotton mask, and again with no mask. Mask surfaces were swabbed with aseptic Dacron swabs in the following sequence: outer surface of surgical mask, inner surface of surgical mask, outer surface of cotton mask, and inner surface of cotton mask. The researchers found SARS COV-2 on all surfaces.

These findings suggest that recommendations to wear face masks to prevent the spread of COVID-19 may not be effective. However the authors noted that 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