Western doctors didn't believe the young Malaysian-Chinese doctor, Wu Lien-teh, who realized that the 1910 Manchurian Plague was transmitted through the air, and that a simple cotton mask could reduce transmission.

But then, everything changed... 1/4
https://99percentinvisible.org/episode/masking-for-a-friend/

In the west, tragically, we forgot this lesson - a lesson we are only re-learning today.

Western docs don't have a great track record of accepting the science of public health hygiene. The scientist who discovered the importance of hand-washing, Ignaz Semmelweis, was mocked and ignored by doctors at the time, and for decades afterwards.
https://www.wnycstudios.org/podcasts/radiolab/articles/dispatch-2-every-day-ignaz-semmelweis-day

Thankfully, the western medical community has remembered the importance of hand-washing for reducing transmission through surfaces, even as they forgot the importance of masks for reducing transmission through the air.

Ignaz Semmelweis went mad before he could see how his discovery of the power of hand washing transformed western medicine.

I am hopeful that this will not be the case for advocates of mask use in the 21st century...