Seoul, Both surgical and cotton masks were found to be ineffective for preventing the dissemination of SARS-CoV-2 (coronavirus) from the coughs of patients with COVID-19, according to a new study.

The study, published in the journal Annals of Internal Medicine, conducted at two hospitals in Seoul, South Korea, found that when COVID-19 patients coughed into either type of mask, droplets of virus were released to the environment and external mask surface.

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 University of Ulsan College of Medicine in South Korea instructed four patients with COVID-19 to cough five 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: the outer surface of a surgical mask, the inner surface of a surgical mask, the outer surface of the cotton mask, and the inner surface of the 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.

"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," the researchers noted.