The general public received confusing information on face masks for preventing viral infections. Some health experts, politicians told people masks are not needed. While Asian governments recommended people to wear faces masks because of the painful memory of 2003 SARS epidemic.
The face masks played an important role in the control of the epidemic 1910 pneumonic plague, which can transmit from person to person by infectious droplets [from CDC.gov]. Dr. Wu Lien Teh, who was nominated for the Nobel Prize in Medicine in 15 years later, invented an affordable sanitary mask to protect people from respiratory droplets. Dr. Wu advised people to wear masks extensively. At the same time, Dr. Mesny, a French doctor who refused to wear masks, died after being infected. The widely used masks and other isolation strategies ended this pneumonic plague pandemic in less than 3 months and avoided a national pandemic.
Even though pneumonic plague and Covid-19 are totally different disease, their transmission are similar. Please avoid unnecessary trials and errors .
Reassuringly, just like the Austrian government, the world is reconsidering advising the public to wear masks.