What makes you ask this question?
For potentially infectious splatter, you should rise with running water for several minutes and consult your doctor for additional advice.
As for sharps, they should not be disposed off in regular trash bag. Even if the sharp is clean, people don't know that. How would the garbage man feel if he gets stuck. How would you feel if you were in his place. Have common courtesy. When I put broken glass / nails / etc in the garbage, I will tape a very visible caution note on the garbage bag. If he see me, he thanks me everytime for thinking of him and his job. Have common courtesy. It's not hard and it's the responsible and right thing to do.
Sounds like **criminal** intent - you may want to contact local police.
If this really happens, the person affected must be tested for several infections.
oh lord.. this is good !!