I did not, I only sent a thank you to McGovern so far because I really felt a strong connection with them and my interviewer explicitly asked me to reach back out to them and gave me their cell and email. That being said, I sent a personal thank you to them after 3 weeks and a short and more general thank you to the admissions email at the same time. Received short, kind replies.
If you felt that your UTMB interview went exceptionally well, I would reach out with a thank you, to admin email. The MMI format makes it difficult to have enough for a personal thank you to each interviewer.
Thats my 2 cents, thank yous are still kinda debated in terms of appropriateness and id rather not come off as uncouth. Best of luck to you! Id be very interested to know what you end up doing!