what disease are you referring to? for covid-19, a surgical mask of practical use 80% single sided (user only) , 95% double sided (both user & patient). but that is single-use surgical mask, proper use.
in reality we dont achieve proper use in public and we are not using surgical grade mask in the open.
Let's say flu category like COVID-19 and the recent Flu A.
This is the common one priced abovee average. Does it work more effectively to reduce spreading or reduce infection?
simple answer: no difference. the efficacy will be about similar to a medical grade 3-ply
most study only focus on 3 domain :
3-ply medical grade,
n95,
cloth masked.
all these in-between have no clear evidence
a 3-ply face mask is generally good for most time. drs have been using it even before covid. a n95 is only necessary in aerosolized situation (like a dentist doing scaling) while cloth mask is not effective
