Aah, HGSE definitely said that interviews are a necessary component of admissions process.
"Once all applications have been reviewed, HGSE will invite selected Ph.D. applicants for a required online interview with members of the admissions committee. Interview dates will be in January, with precise dates to be determined." (Link: https://www.gse.harvard.edu/admissions/apply/phd)
Even I didn't receive an invite.. safe to say that we can prepare for the worst now!
(but congratulations to all who did get an invite )