A new coronavirus outbreak, which originated in the Chinese city of Wuhan and has spread throughout Asia and globally, has prompted people around the world to buy medical face masks in hopes of preventing infection.

Retailers in the U.S. and across the Internet are running out of antiviral face masks as the number of confirmed cases of the coronavirus (2019-nCoV) now exceeds 9,700 globally. More than 200 people have died from the virus in China, where the majority of the 2019-nCoV cases have been detected. The World Health Organization declared a global health emergency on Thursday as the outbreak continues to spread. As of Friday morning, the United Kingdom and Russia had both confirmed their first cases of the viral infection.

Local government officials in Wuhan have required that people wear face masks when they go out in public places to prevent the spread of infection. Health experts tell TIME that such a move is probably effective in the city, where a person is more likely to come in contact with someone who is infected than in other parts of the world.

Read the entire story at Time. Peter Rabinowitz, Director of the UW MetaCenter for Pandemic Disease Preparedness and Global Health Security, is quoted.