On March 13th, the PTAB issued the following notice:

Until further notice, examiner and examining attorney interviews, Patent Trial and Appeal Board (PTAB) and Trademark Trial and Appeal Board (TTAB) oral hearings, and other similar in-person meetings with parties and stakeholders scheduled to take place at USPTO offices on or after Friday, March 13, 2020 will be conducted remotely by video or telephone. Parties will receive further instructions on how to participate by video or telephone in advance of the interview, hearing, or meeting.

If you have any questions, please contact the following:

• For patent examiner interviews, please contact the examiner or the examiner’s supervisor (SPE) directly. Additionally, if you have any questions about telephonic or video interviews in general or are unable to reach the examiner or SPE with respect to a particular interview, please email: ExaminerInterviewPractice@uspto.gov
• For trademark examining attorney interviews, please contact the managing attorney.
• For PTAB oral hearings, please contact PTABHearings@uspto.gov or call 571-272-9797.
• For TTAB oral hearings, please contact TTABHearings@uspto.gov or call 571-272-8500.
• For other in-person meetings, please contact your USPTO point of contact for that meeting

PTAB oral hearings appear to be proceeding as scheduled by video conference.  For example, in IPR2019-00271, where oral argument is scheduled for Wednesday, March 18th, the PTAB issued an order on March 13th instructing the parties to contact the PTAB Hearings phone number to receive video set-up information.  Audio connection information will be available as a backup. A copy of the order in that case is available here.