Biomedical PhD Waitlists?

[Polar Bear]

I had a quick question for all you experts out there. I've applied to a lot of different biomedical PhD programs and I've been invited to three interviews, but I was looking at the big interview thread at the top of this forum and noticed that a lot of schools I haven't heard from yet have their interview weeks coming up soon, which probably means I didn't get an interview at those schools. I'm just wondering if my rejections are set in stone or if there are waitlists for these types of programs just in case not everybody who gets accepted decides to matriculate. Do many biomedical PhD programs have waitlists, or does it depend on the schools on a case-to-case basis? Is it possible for the schools to send out more waves of interview invitations for weekends that haven't been announced yet? I know I shouldn't be putting all my hopes on these sorts of possibilities, but I'm just curious. Thanks for any help.

Edited January 15, 2011 by Polar Bear