Most people who get dengue suffer from what seems like the flu, only more painful in the joints and muscles. Very few get the dangerous kind, and even fewer die (most often due to not seeking medical help quickly enough, or having underlying health issues). This year Barbados has had 1 death in a population of about 280,000, not counting all the tourists. I'm not sure I would consider that dangerous enough to stop visitng here, and if Key West's statistics are similar or better, I wouldn't worry about going there either.
Just a perspective from someone who lives in a place where dengue is prevalent.
ETA: I am 42, lived in Barbados my whole life, and I have never once had dengue or anything remotely like it that could have been mistaken for something else (i.e. never had even a bad flu). My husband has had it twice without needing medical attention, and it was like the flu except for the rash that eventually appeared.