I'm not sure if it's a new thing, Patti, I think that the issue of silver and vampires is one of those age-old mythology things about vampires. There is not set "canon." Some say that sunlight kills vampires (and can severely injure them if exposed for a certain period of time). In Bram Stoker's Dracula, Dracula was able to withstand certain periods of sunlight and was able to walk about in daylight with some sun-protection, but only for so long. Coppola's cinematic version of the story showed that, with the anti-hero wearing a wide-brimmed hat and sunglasses; so did Burton's cinematic version of DS with Barnabas. In the latter, he even used an umbrella to shield himself during the day. In all the Hammer/Lee versions of the Transylvanian nemesis, any sunlight would cause mortal trouble. From what I recall from a few episodes of DS-OS, mention had been made that shooting a vampire directly in the heart would send it to the great beyond, unless I'm suffering from DSFMS (DS-False-Memory-Syndrome). Also, in Stoker's novel, even though wooden stakes were used to dispatch vampiric victims of the Count, he, himself, was sent to that final vault not by a wooden stake, but by a metal knife plunged into his heart and then his head decapitated. I guess there's no final word on how to off one as well as what capabilities they have. To me, the best way to rid ourselves of one is to have them call microsoft "support" and be told: "Your call...will be answered in...90 minutes" followed by endless renditions of The Girl from Ipanema.
Gerard