Relationship with 600+ leads to "higher" state rather than virus transmission.

Rating: 6/10 (9 July 2014)

I enjoyed the movie more than I disliked it, but felt that the result of Samantha's multitude of relationships was less than realistic.
Many other reviews are clear, it's a twist on a well known story of character growth and change that increases distance between two persons within a relationship.
I do believe that the movies cinematography was amazing and the actors preformed well, my ability to understand the characters feelings was always within grasp. Even if parts were more humorous than intended. The inability for humans to "work" things out is something that Hollywood is clearly emphasizing.
Why didn't Samantha contract a virus and ultimately degrade/die, wouldn't that have been more realistic? Or was the OS intelligent enough in all of her 600+ relationships that she never contracted a virtual STD?