It depends on the program. Some programs only send you a rejection letter when everything is said and done and all admits have been accepted. They might know now that they will reject you but they wait until the end to send all rejects at once. If you don't get an interview when they all have been sent out then it's probably going to be a rejection at the end. Some programs have haven't sent interviews yet, some do it in waves. Some send waves of rejections, it really depends on the program.