BU is a public health school with one of the highest ratios of accepted students to matriculated students, and in fact used to the highest and might still be, ergo to try to to figure out who would actually attend the school they'd give out acceptances in December or January and begin the process of waiting to see what happens. It is ALL a game at this point with schools like BU, they'd probably want to know what other schools you applied to in order to gauge what sort of financial assistance you'll get, and they might ask you to provide more information about why'd you think of going to their school as otherwise you might be sitting on their waitlist for a longtime while really you're planning on going elsewhere to better options.
If you want to do something Epi or global health related, there are a lot of more established schools you can go to, where you go for public health school isn't that much of a big deal as even the top school have high admission rates, the issue is getting hard skills, externships, and working hard and networking, and keeping your student loan burden down! I don't think it is prudent to consider BU unless you get a hefty merit scholarship or a part-time teaching position at the school as the tuition cost is massive and makes NO sense for people entering public health which is a competitive field to find a job and is relatively low paying, especially with the high cost of living in Boston.
BU claims to be a "top five private public health school", but in reality they are ranked something like 10th as there are many great public health schools that are public institutions, though the ranking methodology is flawed and doesn't necessary correlate with quality of the education. BU makes a lot of misleading statements, or at least pushes misleading statistics, about their program of education in order to lure students in, which I think is an issue as the school's interests don't overlap with the student's necessarily in that they want to increase tuition dollars coming into the program. BU also did away with the GRE for the public health school starting in 2020 as they claimed it was unfair to female students, though they've got the highest percentages of female students out of most public health schools, they also pushed really hard to keep vaping and vaping flavors unregulated. In reality they did away with the GRE as they need more students, if you feel even half-way confident about your application/experience/education, definitely ask for a significant merit scholarship, they know that if they don't fill all the seats they will lose money. On rankings of student's perception of their public health school on things like friendliness towards students, BU doesn't even make that list, students definitely aren't treated equitably at this school.