@orchidbloom, it’s more likely to be a rejection. I’ve seen it happen all of the time with my former students. The information doesn’t change much. The OP has to have back-ups and can’t pin all his/her hopes on one school.
@"aunt bea" I completely agree with you, although I have to say that its most likely going to be rejection for all applicants overall. Some schools actually have slightly higher acceptance rates for deferred applicants, but I can’t say for Harvard because their deferral rate is so high.
Nevertheless, Harvard is my first choice for several reasons, not just prestige and fame. I have applied to many other schools, including matches and safeties, that I would be happy going to, but I’m not giving up hope on Harvard especially when I have a second chance.
I do not think it is notable, more like ‘of moderate interest’. If they already know, then they already know. I do think a letter of continued interest in fine, but I think you need to tell them something that you didn’t already tell them.