A month or so ago I went fishing with a vaccinated friend, the only vaccinated friend I have. After spending the day with him I came down with what I self diagnosed as giardia. I did a round of metronidazole and whatever I had cleared up. In the back of my mind I have wondered if something was shed on me from the vaccine.
Negative, have not and will not ever get tested.
Just spent the day with a vaccinated person.