Help me find a book I read as a teen!!!!

I don’t remember the name or author and have been trying to find it for forever.

Basically it’s about these teens who go to a beach town or something on the water for the summer, but then they start disappearing or dying. It turns out that there are vampyres(written like that) killing them off.

I remember there being a carnival and a Ferris wheel in the book events but not much else!! Also the vampyres can’t come in unless invited.