I was accepted less than 2 weeks after my interview but not that is not typical. It all depends on when your interview is....Tufts basically has 3 days on which their adcom meets. These 3 days are the end of each of the three interview sessions (i.e. there is one day at the end of december for the oct-dec interviews, a day at the end of february for the jan-feb interviews and one at the end of april for the march-april interviews).....So if you interviewed at any point in jan-feb, you will hear at the end of february regardless of your interview date.
I was lucky in that I interviewed on the last date of the December session (12/6)...that is why it only took 2 weeks to get my acceptance. Hope that helps!