Patients should wear a simple surgical mask as it reduces the spread of droplets from their mouth and nose.
If patients and non infected people all wear masks that reduces spread by 80-90%
If only non infected people wear masks risk is only reduced by 30%
The main component in the equation is the infeected person containing the droplets on the inside of their own mask.
That's what my health and social care employer is telling us in internal documents atm.
If anyone is infected everyone has to wear masks. If the patient cannot wear a mask (we work with people with learning disabilities, neurological differences and psychiatric disorders which make this unrealistic for many) we get FFP3 masks.
So just wearing a 3 ply surgical mask or any dust mask yourself is only marginally protective.
Masks need changing very frequently. We've been told to make one do for a whole shift now but they usually need changing between patients.
There's certainly no benefit in using the same mask/ filter for more than a day.