Is this from the novels? because from what I ahve seen of the TV show (upto date with 3rd season) vampires had no issue been awake during the day as long as they avoided direct sunligh and even then it took a long time for a vampie to die to direct sunlight from what we were shown. Just so you know I am basing my stuff all on the TV show I have not read the novels as I prefer the TV show 
In the books only the
really old vampires can be functional during the day. There is a scene, in the Dallas book, where Sookie has to move Bill during the day and it's very difficult, he is so lethargic. The TV show shows the leaking blood, but I don't remember that from the books because the vamps aren't shown during the day.
I'm not sure a vampire has died from the sun in the books except for Godric and the sleeping vamps exposed by an explosion. (The Fellowship of the Sun blew up a hotel holding a vampire convention.)
As you noted the TV show has differences from the book. I think it's cool to see the alternate endings/stories shown on TV.
