The Our World in Data site is probably the best resource for COVID-19 data.
Compiling these details primarily for sharing with my family, who complained “We don’t even know who to trust anymore”. If anything here’s inaccurate, please let me know so I can fix it!
Update: there appears to be some evidence that viral load does matter, and that even cloth or surgical masks can reduce your exposure. (source)
Surgical and cloth masks reduce the likelihood that the wearer will transmit the disease by blocking large particles. They do not meaningfully prevent the wearer from contracting COVID-19.
N95 masks filter out 95% of airborne particles. Does actually reduce exposure to the wearer, but official guidance is that proper fit is required, one-time-use is recommended, etc.
My take is that the CDC and WHO would be recommending these masks to everyone, but there’s a global shortage and healthcare workers are the most essential personnel right now, so the general public shouldn’t try to get N95s so they go to hospitals.