You don't think exchanging needles only encourages people to do more drugs? And the opposite problem that probably occurs is that drug users are too lazy to go exchange needles, especially the homeless ones.
And then there's this...From April 23, 2019:
San Fransisco Streets Flooded with Dirty Used Needles
Yeah, that needle exchange program is working real good.
There are countless reasons for disease outbreaks but CLEAN needles are not one of them