The dangers of writing to a trend... Basically a long tweet.
Think about the publication process. Not only is the journey to creating an original piece difficult, it's also time consuming. I'm not an expert in the market, but any book start to finish will take YEARS. Now, your trend might last for years, (I do think this vampire thing has lasted awhile) and you could possibly have your work bumped up if it meets a need, but do you want to play like everyone else? By the time you give your work the time and attention it deserves, the trend will either be OVER, or people will be getting... Well, bored. Write something different. Don't abandon your project, but make it unlike any other. Write out of your comfort zone, write something you want to read- that doesn't already exist. ;)