I don't think that's how things work. Infection is a probabilistic thing. Maybe you'll get infected and maybe you won't. A high quality mask properly fit and worn according to an exacting protocol will reduce your risk of infection by X. Compromising on any of those factors may mean your risk is only reduced by Y and Y is less than X, but that doesn't mean it's a complete waste to wear a mask without a clean room or without fitting.

In one of the articles linked in this thread there is a study showing mask usage in children is nearly as effective as intervention against flu as vaccines are. I only read the summary of that paper but I don't think the children are working with clean zones or following doffing procedures carefully.

The article does mention that the effectiveness of masks was greater along older children. To me, that connects with what I wrote earlier. The better you are about using your mask, and here I expect mask diligence comes with age, the better a result you will have, but something is still better than nothing.

Oh, so that's why every hospital room has an air sealed clean zone that medical professionals have to enter to put on ppe?

For those that don't know, this is sarcasm. Most ICUs don't have any sort of sealed off clean zone.

> Most ICUs don't have any sort of sealed off clean zone.

Right - most ICUs aren’t set up to handle infectious diseases.

Here’s the CDC recommendation on doffing procedure. Note the repeated mention of the “doffing area”: https://www.cdc.gov/vhf/ebola/hcp/ppe-training/n95Respirator...