Well I have gotten pink eye and others have also gotten pink eye after coming in contact with an active infection. Though I don't know if that was from a handshake or if it was from a person touching a surface or door handle.

And I know someone that got food poisoning and ended up in the hospital because the server did not wash their hands properly. That server ended up putting a few people in the hospital.

So I have been affected in the past and know people who have been affected because of lack of hygiene.