Masks are 'a very sensible precaution' while scientists work to study exactly how the new virus is transmitted.
All viruses are small enough to get through a typical strap-on medical mask, but the germs don't generally spread through the air one at a time, said Dr. Mark Denison of Vanderbilt University Medical Center in Nashville. Denison studies Sars and Mers, which are coronaviruses, the same family as the new virus.
Masks can block large droplets from a sneeze or cough. That means they have some value, Denison said.
Also, someone in a mask can't touch their own nose and mouth. That can prevent the wearer from picking up germs left on surfaces by someone who is sick, he said.
Masks are "a very sensible precaution" while scientists work to study exactly how the new virus is transmitted, said University of Oxford researcher Trudie Lang.
None of this, however, is based on rigorous research. Nobody has compared groups of masked and unmasked people by exposing them to the new germ, Denison said. A 2017 review of studies in health care workers suggested masks offer some protection against SARS, but the authors noted "existing evidence is sparse and findings are inconsistent."
The best way to avoid getting sick from the new virus is to wash your hands with soap and water. If soap and water aren't available, use an alcohol-based hand sanitizer. That's the same advice for avoiding regular cold and flu viruses.
Unicef said Wednesday it has shipped six metric tons of respiratory masks and protective suits to China for use by health workers.
Masks have been commonly used in some countries when wearers are sick, fighting allergies or on days when air pollution is bad. The new virus has fueled demand for them around the world.
In Taiwan, where the holiday is over, factories are up and running. Premier Su Tseng-chang said the government had already distributed 23 million masks and that Taiwan will be able to produce 4 million more a day.
A mask factory in Shanghai has gone into overdrive despite the holiday.
"We are now working 24 hours, 2 shifts a day, 12 hours shift," said Liao Huolin, president of the mask company. "We violated labor law," Liao said, "but the workers understand."