I had a panic attack reading this comment. haha
I just checked the Population Health Sciences FAQ page (http://www.hsph.harvard.edu/phdphs/admissions-faq/) and found this:
Is the admission based on some entry test and/or interview or is done on the basis of the academic history?
Applications are reviewed on the basis of academic credentials, GPA, GRE, TOEFL, prior research and work experience, statement of purpose, recommendations and a writing sample. No other entry test or interview is required.
I spoke with a rep from this department in October, and she said that the department doesn't plan on interviewing candidates. Maybe it's case specific?